Breathing assistance apparatus

ABSTRACT

Breathing assistance apparatus for treating sleep apnoea are described. More specifically, nasal interface for the supply of respiratory gases, but most particularly positive pressure gases are described. The nasal interfaces may include various forms of nasal pillows or nasal plugs. Associated elements such as manifolds or housings to hold or secure the pillows or plugs, or headgear are also disclosed.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference and made a part of thepresent disclosure.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a breathing assistance apparatus fortreating sleep apnoea. More specifically, the present invention providesnasal interface for the supply of respiratory gases, but mostparticularly positive pressure gases.

The invention also relates to a patient interface which includes nasalpillows, or nasal plugs and which may also include associated elementssuch as headgear.

Description of the Related Art

Obstructive Sleep Apnoea (OSA) is a sleep disorder that affects up to atleast 5% of the population in which muscles that normally hold theairway open relax and ultimately collapse, sealing the airway. The sleeppattern of an OSA sufferer is characterised by repeated sequences ofsnoring, breathing difficulty, lack of breathing, waking with a startand then returning to sleep. Often the sufferer is unaware of thispattern occurring. Sufferers of OSA usually experience daytimedrowsiness and irritability due to a lack of good continuous sleep.

In an effort to treat OSA sufferers, a technique known as ContinuousPositive Airway Pressure (CPAP) was devised. A CPAP device consists of agases supply (or blower) with a conduit connected to supply pressurisedgases to a patient, usually through a mask, nasal prongs, plugs orpillows. The pressurised air supplied to the patient effectively assiststhe muscles to keep the patient's airway open, eliminating the typicalOSA sleep pattern.

The procedure for administering CPAP treatment has been well documentedin both the technical and patent literature. Briefly stated, CPAPtreatment acts as a pneumatic splint of the airway by the provision of apositive pressure, usually in the range 4 to 20 cm H2O. The air issupplied to the airway by a motor driven blower whose outlet passes viaan air delivery hose to a nose (or nose and/or mouth) mask sealinglyengaged to a patient's face by means of a harness or other headgear.

It is known to provide a flow of respiratory gases to a user via a nasalcannula to relieve a number of ailments, for example, sleep apnoea orsnoring. One problem with supplying a flow of gases to a user via aninterface such as a nasal interface, prongs or plugs (“nasal interface”)is that it can be difficult to form a good seal between the nasalinterface and the user's nostrils. The nasal interface is often held inplace against the user's nose by headgear worn on the user's head. Thehead gear may be over tightened so that the nasal interface is presseduncomfortably onto the user's nose. Alternatively the headgear may beapplied to the user's head too loosely, preventing an effective sealbeing formed between the interface and user's nostrils. Also, the sealbetween the interface and the user's nostrils may be broken if theinterface is knocked while the user sleeps, or if the user moves whilesleeping.

There are a number of different mechanisms which are known in the artwhich are intended to offer a solution to this problem.

U.S. Pat. No. 4,782,832 describes a nasal puff assembly with a pair ofbellows type corrugated nare elements designed to sit adjacent to andpartially within the nose of the user. The assembly includes a hollowplenum to which the pair of nare elements are operationally connected.The plenum is configured to allow the nare elements to rotate and alsoshift laterally in order to custom fit the assembly to a wide variety ofusers.

US 2006/0107958 describes an adjustable ventilation interface includinga nasal cannula body. The cannula body has a pair of nasal prongs thatare adjustable with respect to each other. The nasal prongs are locatedon the top portion of the nasal cannula body to create a sealinginterface with a user's nose. The cannula body has first and secondbellows-like structures. The first bellows like structure providesadjustability in a centre-to-centre distance between the nasal prongs.The second bellows-like structure creates a sealing engagement with abottom area of the user's nose. The nasal prongs have thin corrugatedwalls that are designed to inflate under pressure. In a compressed orfolded state the prongs can be easily inserted into a user's nose. In aninflated state the prongs assume a barrel-shaped structure to provide alarge, even sealing surface in the nares. The prongs are folded orcorrugated when not in use, so that their outer perimeter or profile issmaller than when they are inflated. This allows them to be easilyinserted into the user's nostrils. In use the prongs inflate and sealagainst the user's nostrils. Because the inner surface of the user'snostrils is smooth, in use when the gas is flowing through the prongs,the prongs will inflate and have a smooth outer surface.

U.S. Pat. No. 6,431,172 describes a nasal cannula with an inflatableplenum chamber mounted on a rigid support. A pair of nares elements aremounted on the inflatable plenum chamber for insertion into the nostrilsof the user. The inflatable plenum chamber is flaccid when notpressurised and not effective in transmitting forces between nareselements and the rigid support. When inflated the inflatable plenum actsto absorb shocks and jolts without transmitting the shocks and jolts tothe user. The inflatable plenum provides additional degrees of freedomfor movement of the nares elements while at the same time increasing therange of movement in all directions to accommodate large physicaldifferences between users. For example each nares element can moveaxially, laterally, rotate and tilt.

The prior art further includes a nasal pillows interface in whichheadgear retains a soft plenum in the vicinity of the user's nose. Apair of flexible protrusions engage against the nares of the recipient.Typically, the protrusions are able to axially compress and have alateral freedom of movement relative to the supporting cushion. Examplesare the ResMed Mirage Swift™ II, or the Fisher and Paykel Opus™ 360interfaces or nasal masks. A variety of different pillow configurationswhich could be used with these interfaces are described and shown in WO2008/014543 and US 2009/044808.

The prior art still further includes a nasal cannula interface. Thenasal canal interface includes a plenum portion that rests against theupper lip of the user and a pair of prongs. Each prong extends into thenostril of the user. An example is the Nasal-Aire interface made byInnomed, where gases are provided to the interface and the prongs byconduits or hoses that extend from the users nose across their cheeks,over their ears and around the back of their head.

Interfaces such as those described above are frequently used fordelivering pressurised gases to a person being treated for obstructivesleep apnea (OSA) or other sleep disorders. These users typically wearthe interface in a home sleeping environment. Comfort and effectivesealing even under conditions of patient movement are majorconsiderations.

In this specification where reference has been made to patentspecifications, other external documents, or other sources ofinformation, this is generally for the purpose of providing a contextfor discussing the features of the invention. Unless specifically statedotherwise, reference to such external documents is not to be construedas an admission that such documents, or such sources of information, inany jurisdiction, are prior art, or form part of the common generalknowledge in the art.

The term “comprising” as used in this specification means “consisting atleast in part of”. When interpreting each statement in thisspecification that includes the term “comprising”, features other thanthat or those prefaced by the term may also be present. Related termssuch as “comprise” and “comprises” are to be interpreted in the samemanner.

SUMMARY OF THE INVENTION

It is an object of the present invention to attempt to provide aninterface that goes some way to overcoming disadvantages in the priorart or which will at least provide the industry with a useful choice.

In a first aspect the present invention consists in a nasal interfacefor supplying a flow of respiratory gases to a user comprising: headgear, in use the head gear being fitted to the user's head, a manifoldhaving a manifold inlet, in use the manifold being attached to the headgear so that the manifold locates adjacent the user's nose, the inletadapted to in use receive a flow of gases from a gases supply, a pair ofnasal pillows, each nasal pillow comprising a nasal puff and a tubularbase, the nasal puff being connected to and in fluid communication withthe tubular base, in use, each said tubular base being attached to andin fluid communication with the manifold, the tubular base and the nasalpuff adapted to allow the flow of gases to enter the pillow through thetubular base and exit the pillow through the nasal puff, the pair ofnasal puffs sealingly engaging with the user's nostrils, each saidtubular base having a ribbed section which extends at least part wayaround the circumferential perimeter of the tubular base, the ribbedsection formed by a plurality of thick walled portions spaced apart,each thick walled portion being separated from adjacent thick walledportions by intervening thin walled portions.

In a second aspect the present invention consists in a nasal pillow foruse with a nasal interface for supplying a flow of respiratory gases toa user, the nasal pillow comprising:

-   -   a nasal puff and a tubular base, the nasal puff being connected        to and in fluid communication with the tubular base,    -   the tubular base and the nasal puff adapted to allow the flow of        gases to enter the pillow through the tubular base and exit the        pillow through the nasal puff, in use the nasal puff sealingly        engaging with the user's nostril,    -   the tubular base having a ribbed section which extends at least        part way around the circumferential perimeter of the tubular        base,    -   the ribbed section formed by a plurality of thick walled        portions spaced apart, each thick walled portion being separated        from adjacent thick walled portions by intervening thin walled        portions.

In a third aspect the present invention consists in a nasal cannulaassembly for use with a nasal interface for supplying a flow ofrespiratory gases to a user, the nasal cannula assembly comprising:

-   -   a manifold having a manifold inlet, in use the manifold being        located adjacent the user's nose, in use the inlet receiving a        flow of gases from a gases supply,    -   a pair of nasal pillows, each nasal pillow comprising a nasal        puff and a tubular base, the nasal puff being connected to and        in fluid communication with the tubular base,    -   in use, each said tubular base being attached to and in fluid        communication with the manifold, the tubular base and the nasal        puff adapted to allow the flow of gases to enter the pillow        through the tubular base and exit the pillow through the nasal        puff, the pair of nasal puffs sealingly engaging with the user's        nostrils,    -   each said tubular base having a ribbed section which extends at        least part way around the circumferential perimeter of the        tubular base,    -   the ribbed section formed by a plurality of thick walled        portions spaced apart, each thick walled portion being separated        from adjacent thick walled portions by intervening thin walled        portions.

In a fourth aspect the present invention consists in a system forsupplying a flow of respiratory gases to a user comprising:

-   -   a blower for supplying the flow of respiratory gases through the        system,    -   a humidifier unit, the blower supplying the flow of respiratory        gases to the humidifier unit, the humidifier unit humidifying        the flow of respiratory gases to a humidification level,    -   a conduit for transporting the flow of gases from the        humidification unit to a nasal interface, in use the nasal        interface supplying the flow of respiratory gases to a user, the        nasal interface comprising:    -   head gear, in use the head gear being fitted to the user's head,    -   a manifold having a manifold inlet, in use the manifold being        attached to the head gear so that the manifold locates adjacent        the user's nose, the inlet adapted to in use receive a flow of        gases from a gases supply,    -   a pair of nasal pillows, each nasal pillow comprising a nasal        puff and a tubular base, the nasal puff being connected to and        in fluid communication with the tubular base,    -   in use, each said tubular base being attached to and in fluid        communication with the manifold, the tubular base and the nasal        puff adapted to allow the flow of gases to enter the pillow        through the tubular base and exit the pillow through the nasal        puff, the pair of nasal puffs sealingly engaging with the user's        nostrils,    -   each said tubular base having a ribbed section which extends at        least part way around the circumferential perimeter of the        tubular base,    -   the ribbed section formed by a plurality of thick walled        portions spaced apart, each thick walled portion being separated        from adjacent thick walled portions by intervening thin walled        portions.

In a fifth aspect the invention consists in an interface for use as partof an apparatus for providing a stream of gases to a user, comprising:

-   -   a manifold, including a gases supply aperture adapted for        connection to a flexible and lightweight gases supply conduit or        tube in use to receive a stream of gases therefrom,    -   a pair of supple nasal pillows fluidically connected to said        manifold so that in use said stream of gases passes through said        nasal pillows, said nasal pillows adapted to substantially seal        against the nostrils of a user in use, so that substantially the        whole of said stream of gases is delivered to said user,    -   a pair of connecting arms extending generally one from each side        of said manifold in use and adapted for connection to a headgear        or similar, said connecting arms and said pillows each formed        from the same or similar materials, so that said connecting arms        and said pillows have the same or substantially similar        flexibility and suppleness.

In a sixth aspect the invention consists in an interface assembly foruse as part of an apparatus for providing a stream of gases to a user,comprising:

-   -   a flexible and lightweight interface gases supply tube or        conduit having a first or distal end and a second or proximal        end, said first or distal end adapted to receive a gases stream        from a gases supply apparatus in use,    -   a manifold, including a gases supply aperture, said second end        and said gases supply aperture mutually adapted for connection        so that in use said manifold receives said stream of gases,    -   a pair of supple and flexible nasal pillows fluidically        connected to said manifold so that in use said stream of gases        passes through said nasal pillows, said nasal pillows adapted to        substantially seal against the nostrils of a user in use, so        that substantially the whole of said stream of gases is        delivered to said user,    -   a pair of connecting arms extending generally one from each side        of said manifold and adapted for connection to a headgear or        similar, said connecting arms and said pillows each formed from        the same or similar materials, so that said connecting arms and        said pillows have the same or substantially similar flexibility        and suppleness.

In a seventh aspect the invention consists in an interface for use aspart of an apparatus for providing a stream of gases to a user,comprising:

-   -   a manifold, including a gases supply aperture adapted for        connection to a flexible and lightweight gases supply conduit or        tube in use to receive a stream of gases therefrom,    -   a pair of supple nasal pillows fluidically connected to said        manifold so that in use said stream of gases passes through said        nasal pillows, said nasal pillows adapted to substantially seal        against the nostrils of a user in use, so that substantially the        whole of said stream of gases is delivered to said user,    -   a pair of connecting arms extending generally one from each side        of said manifold in use and adapted for connection to a headgear        or similar,    -   said manifold configured so that in use said gases supply        aperture is aligned substantially vertically downwards, said        manifold and said pillows configured so that said interface will        not extend beyond the end of the nose of an average user in use.

Preferably said manifold is formed from a rigid or semi-rigid material,said interface further including a gasket formed from a supple andflexible material, said gasket connected or attached to said manifold inuse, said nasal pillows connected to said gasket.

Preferably said manifold includes a substantially open upper portion orface, and said gasket is adapted to connect over the top of said openupper portion.

Preferably said manifold is configured so that in use said gases supplyaperture is aligned substantially vertically downwards.

Preferably said manifold, said gasket and said pillows are configured sothat said interface will not extend beyond the end of the nose of anaverage user in use.

Preferably at least said gasket and said connecting arms are formed as aunitary or one-piece item.

Even more preferably said gasket, said connecting arms and said pillowsare formed as a unitary or one-piece item.

Preferably said gasket includes an open portion which in use isstretched over the outside of the open upper face of said manifold sothat said gasket covers and closes the open face of the manifold, withsaid gasket sealing against the outer surface of the manifold.

Preferably said gases supply aperture is adapted for connection to aflexible and lightweight gases supply conduit by way of a male-femalepush-fit connection.

Alternatively said gases supply aperture is adapted for connection to aflexible and lightweight gases supply conduit by way of a ball jointconnection.

Preferably each of said arms has an L-shape in profile, one face of theL-shape of each arm resting against the face of a user in use.

Preferably said manifold includes a limited flow outlet for providinggas washout from said interface.

Alternatively said proximal end of said gases supply conduit includes alimited flow outlet for providing gas washout from said interface.

Preferably said gasket includes a lip cushion located on the rear ofsaid interface and resting against a users top lip in use.

Preferably said lip cushion is sealed from said flow of gases.

Alternatively said lip cushion receives part of said flow of gases inuse and at least partially inflates.

Preferably said connecting arms are integrally connected with saidmanifold and said gasket, said connecting arms and said pillows formedas a unitary or one-piece item, said gasket including an open portionwhich in use is stretched over the outside of the open upper face ofsaid manifold so that said gasket covers and closes the open face of themanifold, with said gasket sealing against the outer surface of themanifold.

Alternatively said gasket and said pillows are integrally connected tosaid manifold, said arms formed as a unitary or one-piece item, mergingat their inner ends into a hollow aperture which is shaped and sizedwith the outer sides or surfaces of said gasket and said manifold, saidmanifold in use passed into said hollow aperture so that said manifold,or said gasket, or both wedge into said hollow aperture.

Preferably said gasket includes a flared portion from the outer parttowards the inner part closest to a user, and said hollow aperturecorresponds to said flared portion, so that when said manifold is passedinto the hollow aperture, that part of said manifold which forms thegases supply aperture and the outer part of the manifold which includesthe limited flow outlet passes through the aperture and the inner partof said manifold and said gasket wedges into said hollow aperture.

Preferably said interface assembly further includes a lanyard, saidlanyard forming a loop, one point on said loop connected at or close tothe distal end of said supply conduit.

Preferably said interface assembly further includes a lanyard, saidlanyard formed as two separate lengths, the outer ends of said lengthsconnects at or close to the distal end of said supply conduit, the innerends of said lengths connected to said headgear.

Preferably said flexible and lightweight interface gases supply tubewill not support its own weight when held at one end in such a mannerthat the main body of the conduit extends outwards from the held endgenerally horizontally, and over a 20 to 30 cm length of supply conduithaving a typical diameter of 1 to 2 cm and a wall thickness at the ribsof 1 to 3 mm and a wall thickness between the ribs of less than 1 mm,the unsupported end of the supply conduit will bend and ‘droop’ so thatthe unsupported end points substantially or directly downwards or bendsthrough at least 70 degrees over this length.

In an eighth aspect the present invention consists in a nasal plug forinserting in a patient's nare to supply gases to said patientcomprising:

-   -   a foam body with a bore there through for the passage of said        gases,    -   a skin, substantially covering the exterior surfaces of said        foam body.

Preferably said skin is made from a plastics or silicone material.

Preferably said skin extends over the surfaces of said bore.

Preferably said skin is perforated.

Preferably said foam body is tubular with a curved tip.

Preferably said foam body has a tip and an end, with a circumferentialflange there between, said flange in use resting against the externalsurface of said patient nare.

Preferably said nasal plug further comprises a circumferential flapextending downwards from said tip.

Alternatively said nasal plug further comprises a circumferential flapextending upwards from said flange.

In a ninth aspect the present invention consists in a nasal plug forinserting in a patient's nare to supply gases to said patientcomprising:

-   -   a foam body with a bore there through for the passage of said        gases, said foam body having a tip and an end, with a        circumferential flange there between,    -   a skin substantially covering the exterior surfaces of said foam        body, and    -   a circumferential flap extending from one of said tip and said        flange.

In a tenth aspect the present invention consists in a nasal plug forinserting in a patient's nare to supply gases to said patientcomprising:

-   -   a foam body having an inlet and a bifurcated bore there through        for the passage of said gases,    -   two nasal members formed in said foam body, in use extending        into a patient's nares, one each of said bifurcated branches of        said tubular bore extending through each of said nasal member        and terminating in an outlet in each of said nasal member, and    -   a circumferential flange formed in said foam body between said        inlet and said outlets on said nasal members.

Preferably said nasal plug further comprises a coating substantiallycovering the exterior surfaces of said foam body.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that includes a gases supply that produces a streamof gases, a supply conduit that is connected to said gases supply andwhich receives said stream of gases from said gases supply, and apatient interface connected to and in fluid communication with saidsupply conduit and adapted to deliver said stream of gases to said uservia the nares, said pillow section forming part of said patientinterface, said pillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        pillow gasket, said pillow portions adapted to receive said        stream of gases from said pillow gasket and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user,    -   said outer cap having at least one and preferably a pair of ribs        that extend from the inner surface of said outer cap towards        said inner cap, said at least one rib having a height less than        the height of said outer cap, said rib located on said inner        surface of said outer cap so that said at least one rib does not        extend all the way to the top nor all the way to the bottom of        said outer cap.

Preferably said at least one rib is rounded, so that the upper and lowerends of said rib blend with said inner surface of said outer cap.

Preferably said at least one rib is located towards the top of saidinside wall of said outer cap.

Preferably said at least one rib is a pair of ribs, said pair spacedopposite to one another on the perimeter of said inner surface of saidouter cap.

Preferably said rib or ribs are of substantially equal width.

Alternatively the width of said rib or ribs varies over the height ofsaid rib or ribs.

In a another aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that includes a gases supply that produces a streamof gases, a supply conduit that is connected to said gases supply andwhich receives said stream of gases from said gases supply, and apatient interface connected to and in fluid communication with saidsupply conduit and adapted to deliver said stream of gases to said uservia the nares, said pillow section forming part of said patientinterface, said pillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        pillow gasket, said pillow portions adapted to receive said        stream of gases from said pillow gasket and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user,    -   said inner cap having at least one and preferably a pair of ribs        extending from the outer surface of the wall of said inner cap,        said at least one rib not extending the full length or height of        said inner cap, said rib not extending to either of the rim or        the base of said inner cap.

Preferably said at least one rib is rounded so that the upper and lowerends of said rib blend with said inner surface of said inner cap.

Preferably said at least one rib extends between one fifth and fourfifths of the height of said inner cap.

Preferably said rib or ribs is a pair of ribs spaced equidistant aroundthe perimeter of said inside pillow.

Preferably each of said ribs are of equal width.

Alternatively the width of said rib or ribs varies with the height ofsaid rib or ribs.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that includes a gases supply that produces a streamof gases, a supply conduit that is connected to said gases supply andwhich receives said stream of gases from said gases supply, and apatient interface connected to and in fluid communication with saidsupply conduit and adapted to deliver said stream of gases to said uservia the nares, said pillow section forming part of said patientinterface, said pillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        pillow gasket, said pillow portions adapted to receive said        stream of gases from said pillow gasket and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section, said cap connected to the upper end of said        stalk, said cap formed from an inner cap and an outer cap, said        inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user,    -   each of said pillow portions having at least one and preferably        a pair of ribs extending from the rim of said inner cap to the        base of said inner cap, said rib tapering in thickness from zero        at the top rim of said inner cap to a maximum at the base of        said inner cap, and extending across the width of said airgap at        said base.

Preferably said at least one rib or ribs are equally spaced apart aroundthe perimeter of said inner cap.

Preferably said at least one rib is a pair of ribs.

Preferably each of said rib or ribs have substantially the same widthover their height.

Alternatively the width of said rib or ribs varies with the height ofsaid rib or ribs.

Preferably the base of said rib or ribs is thicker than the upperportion of said rib or ribs.

Alternatively the base of said rib or ribs is thinner than the upperportion of said rib or ribs.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that includes a gases supply that produces a streamof gases, a supply conduit that is connected to said gases supply andwhich receives said stream of gases from said gases supply, and apatient interface connected to and in fluid communication with saidsupply conduit and adapted to deliver said stream of gases to said uservia the nares, said pillow section forming part of said patientinterface, said pillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        pillow gasket, said pillow portions adapted to receive said        stream of gases from said pillow gasket and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by a cavity when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user,    -   each of said pillow portions has at least one rib and preferably        a pair of ribs that extend inwards and downwards from the rim of        said outer cap to preferably contact and most preferably connect        with the rim of said inner cap, said rib contacting and most        preferably merging with the outer surface of said inner cap from        said rim of said inner cap to the base of said inner cap.

Preferably said at least one rib or said ribs are spaced substantiallyequidistant from one another around the perimeter of said pillow.

Preferably said at least one rib is a pair of ribs.

Preferably said at least one rib or ribs have substantially the samewidth over their height.

Alternatively the width of said rib or ribs varies with the height ofsaid rib or ribs.

Preferably the base of said rib or ribs is thicker than the upperportion of said rib or ribs.

Alternatively the base of said rib or ribs is thinner than the upperportion of said rib or ribs.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that includes a gases supply that produces a streamof gases, a supply conduit that is connected to said gases supply andwhich receives said stream of gases from said gases supply, and apatient interface connected to and in fluid communication with saidsupply conduit and adapted to deliver said stream of gases to said uservia the nares, said pillow section forming part of said patientinterface, said pillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        pillow gasket, said pillow portions adapted to receive said        stream of gases from said pillow gasket and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user,    -   each of said pillow portions has at least one rib and preferably        a pair of ribs which extend inwards and downwards from the rim        of said outer cap, said at least one rib extending downwards to        the base of said outer cap, in such a manner that there is        always an airgap or cavity between that part, side or edge of        said rib closest to the outer surface of said inner cap, and the        outer surface of said inner cap.

Preferably said at least one rib or ribs are spaced equidistant fromeach other around the perimeter of said inside wall of said outer cap.

Preferably said at least one rib is a pair of ribs.

Preferably said at least one rib or ribs have substantially the samewidth over their height.

Alternatively the width of said rib or ribs varies with the height ofsaid rib or ribs.

Preferably the base of said rib or ribs is thicker than the upperportion of said rib or ribs.

Alternatively the base of said rib or ribs is thinner than the upperportion of said rib or ribs.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that includes a gases supply that produces a streamof gases, a supply conduit that is connected to said gases supply andwhich receives said stream of gases from said gases supply, and apatient interface connected to and in fluid communication with saidsupply conduit and adapted to deliver said stream of gases to said uservia the nares, said pillow section forming part of said patientinterface, said pillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said pillow gasket and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap section and stalk also forming an airway that        acts as a path for said stream of gases to flow through said        pillow section and to said user,    -   each of said pillow portions also having at least one fin which        extends into said air gap and which runs between the rim of said        outer cap and the base of said inner and outer caps, said fin        extending across said pillow portion from one side to the other,        said fin having a central portion located between the inner        sides of said inner cap, the top edge of said central portion        substantially aligned with the rim of said outer cap, the lower        edge of located above the bases of inner and outer caps.

Preferably said fin has parallel sides.

Preferably said fin tapers in thickness, said fin being thicker at itsbase than at its rim.

Preferably said fin extends straight across said pillow section.

Preferably said fin curves across the width of said pillow section.

Preferably the vertex of said curve is centrally located.

Alternatively the vertex of said curve is offset from the centre of saidpillow section.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said pillow gasket and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap and stalk also forming an airway that acts as a        path for said stream of gases to flow through said pillow        section and to said user,    -   each of said pillow portions having a recess that forms an air        gap in said airway, said recess formed at the point where said        inner cap attaches to the top of the stalk, said recess        following the perimeter of said inner cap,    -   each of said pillow portions having at least one and preferably        a series of ribs within the recess.

Preferably said ribs are a series of ribs and are spaced atsubstantially equal intervals around said perimeter.

Preferably said ribs are a pair of ribs, diametrically opposed on saidnasal pillow section.

Preferably said ribs have an inner edge or surface that generallyfollows and is aligned with the inner wall of said inner pillow and saidstalk.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section connected to the upper end of said stalk, said        cap formed from an inner cap and an outer cap, said inner cap        and said outer cap arranged substantially concentrically and        separated by an air gap when not in use, said outer cap        surrounding said inner cap, the outer surface of said outer cap        adapted to substantially seal against the nare of said user,        said cap and stalk also including an airway that acts as a path        for said stream of gases to flow through said pillow section and        to said user,    -   said inner cap thicker at the top edge or rim than at the bottom        edge or base.

Preferably the wall of said outer cap is thinner than the wall of saidinner cap.

Preferably said inner cap gradually tapers in thickness, from being thinat the base to thicker at the rim.

Preferably said inner and outer caps are flared in an upward and outwarddirection from said base, said inner cap flared to a greater extent thansaid outer cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section connected to the upper end of said stalk, said        cap formed from an inner cap and an outer cap, said inner cap        and said outer cap arranged substantially concentrically and        separated by an air gap when not in use, said outer cap        surrounding said inner cap, the outer surface of said outer cap        adapted to substantially seal against the nare of said user,        said cap and stalk also including an airway that acts as a path        for said stream of gases to flow through said pillow section and        to said user,    -   said inner cap having a bead which extends inward from the top        edge of said inner cap, and    -   said outer cap having a bead which extends inward from the top        edge of said outer cap.

Preferably said bead extends in an unbroken ring around the entireperimeter of said outer cap and said inner cap.

Preferably said bead is substantially circular in shape.

Preferably the wall of said inner cap tapers in thickness, said wall ofsaid inner cap being thicker at the base than at said rim or top edge.

Alternatively the wall of said inner cap has a uniform thickness.

Preferably said bead is thicker in cross-section than the wall thicknessof said outer cap and said inner cap.

Preferably said bead applied to said outer cap is substantiallyidentical to said bead applied to said inner cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, said inner and outer caps        having a common base which connects to said upper end of said        stalk, the outer surface of said outer cap adapted to        substantially seal against the nare of said user, said cap and        stalk also including an airway that acts as a path for said        stream of gases to flow through said pillow section and to said        user,    -   said pillow portion having a flange that extends from said        common base upwards into said airgap.

Preferably said flange extends upwards substantially parallel to theinner surface of said outer cap or the outer surface of said inner cap,or both.

Preferably said flange is generally triangular in cross-section.

Preferably said flange tapers in cross section, said flange thicker atits base and thinner at its upper extreme.

Preferably said flange is the same or greater thickness than the wall ofsaid inner cap wall.

Preferably said flange is the same or greater thickness than the wall ofsaid outer cap wall.

In yet another aspect the invention consists in a nasal pillow sectionfor use as part of a system for delivering a stream of gases to a user,said system of the type that has a gases supply that produces a streamof gases, a supply conduit that is connected to said gases supply andwhich receives said stream of gases from said gases supply, and apatient interface connected to and in fluid communication with saidsupply conduit and adapted to deliver said stream of gases to said uservia the nares, said pillow section forming part of said patientinterface, said pillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically, said outer cap surrounding said inner cap, the        outer surface of said outer cap adapted to substantially seal        against the nare of said user, said cap and stalk also including        an airway that acts as a path for said stream of gases to flow        through said pillow section and to said user,    -   said outer cap having at least one bead extending inward from        the inner surface of the wall of said outer cap and around the        perimeter of said outer cap, said bead located below the upper        rim of said outer cap.

Preferably said bead is substantially semi-circular in cross section.

Preferably said bead is thicker in cross-section than said outer capwall.

Preferably the cross-sectional thickness of said bead is substantiallytwice the thickness of said outer cap wall.

Preferably said bead has a constant thickness and runs around the entireperimeter of said outer cap.

Preferably said bead is located in the top one third of said outer cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap and stalk also including an airway that acts as a        path for said stream of gases to flow through said pillow        section and to said user,    -   said inner cap has at least one bead extending outward from said        inner cap and running around the perimeter of said inner cap.

Preferably said bead has a substantially round cross section.

Preferably the cross-sectional thickness of said bead is greater thanthat of said inner cap wall.

Preferably the wall of said inner cap has a uniform thickness.

Preferably the wall of said outer cap has a uniform thickness.

Preferably said bead is located approximately two thirds of the way upthe outer surface of said inner cap.

Alternatively said bead is located at and extends around the rim of saidinner cap.

Preferably said bead has a constant thickness around the entireperimeter of said inner cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap and stalk also including an airway that acts as a        path for said stream of gases to flow through said pillow        section and to said user, said outer cap having at least one        bead extending outwardly from the rim of    -   said outer cap, and running around the perimeter of said outer        cap.

Preferably bead is substantially semi-circular in cross section.

Preferably said bead is thicker in cross-section than the wall of saidouter cap.

Preferably said bead has a constant cross section along its perimeterand said bead runs around the entire perimeter of said outer cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap and stalk also including an airway that acts as a        path for said stream of gases to flow through said pillow        section and to said user,    -   said inner cap including at least one bead extending inward from        the rim of said inner cap and running around the perimeter of        said inner cap.

Preferably said bead has a substantially circular cross section.

Preferably said bead has a substantially constant cross-sectionalthickness.

Alternatively said bead differs in thickness at various points along theperimeter of said inner cap.

Preferably the wall of said inner cap is of uniform thickness.

Alternatively the wall of said inner cap tapers, said inner cap beingthicker at its base than at its rim.

Preferably said outer cap is of uniform thickness.

Preferably said bead has a thicker cross-section than the wall of saidinner cap or said outer cap or both.

More preferably said bead is substantially twice the thickness of thewall of said inner cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap and stalk also including an airway that acts as a        path for said stream of gases to flow through said pillow        section and to said user,    -   said outer cap having a bead located on and around the upper rim        of said outer cap extending inwards.

Preferably said bead is substantially round in cross section.

Preferably said bead is thicker in cross section than the wall of saidouter cap, or said inner cap, or both.

More preferably said bead is substantially twice the thickness of saidouter cap.

Preferably said bead has a constant thickness.

Alternatively said bead varies in thickness at various points around theperimeter of said outer cap.

Preferably the wall of said inner cap is of uniform thickness.

Alternatively the wall of said inner cap tapers in thickness, said innercap being thicker at its base than at its rim.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap and stalk also including an airway that acts as a        path for said stream of gases to flow through said pillow        section and to said user,    -   said inner cap and said outer cap are substantially the same        height so that the rim of said outer cap and the rim of said        inner cap are substantially aligned and planar.

Preferably the wall of said inner cap has a uniform thickness.

Preferably the wall of said outer cap has a uniform thickness.

Alternatively the wall of said inner cap is tapered in thickness, saidinner cap being thicker at its base and thinner at its rim.

Alternatively the wall of said outer cap is tapered in thickness, saidouter cap being thicker at its base and thinner at its rim.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        pillow gasket, said pillow portions adapted to receive said        stream of gases from said pillow gasket and provide said stream        of gases to said user, each of said pillow portions formed from        an air delivery tube, the base of said air delivery tube        connected to said pillow gasket, and a cap section, said cap        section connected to and partially surrounding said air delivery        tube over at least part of the length or height of said air        delivery tube, the outer surface of said cap adapted to        substantially seal against the nare of said user,    -   said air delivery tube having an inner surface with parallel        walls or sides.

Preferably the top edge or rim of said air delivery tube is in line orplanar with the rim of said cap.

More preferably said air delivery tube extends above and out of saidcap, such that the rim of said air delivery tube is located above therim of said cap.

Preferably the internal walls of said air delivery tube are parallel,and the outer walls of said air delivery tube taper, being thicker atthe base of said air delivery tube than at the rim.

Alternatively said cap has a thinner cross-sectional thickness than saidair delivery tube.

Preferably said cap extends above said air delivery tube, such that therim of said cap is above the rim of said air delivery tube.

Preferably the wall of said cap is of uniform cross-sectional thickness.

Alternatively the wall of said cap tapers in thickness such that saidcap is thicker at its base than at its rim.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said stream of gases flowing through said stalk and said        cap section to said user,    -   the wall of said outer cap tapered in cross-sectional thickness        so that said outer cap wall is thicker at the upper rim of said        outer cap than at the base of said outer cap.

Preferably the wall of said inner cap tapers in cross-sectionalthickness such that said inner cap wall is thicker at the base of saidinner cap than at the rim.

Preferably said outer cap is taller than said inner cap, the base ofsaid inner cap and the base of said outer cap co-located so that the rimof said outer cap is above the rim of said inner cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap section and stalk forming an airway that acts as        a path for said stream of gases to flow to said user,    -   said inner cap extending at least partially from the upper end        of said outer cap.

Preferably the wall of said inner cap is thicker in cross-section thanthe wall of said outer cap.

Preferably said inner cap has a uniform thickness in cross-section.

Alternatively said inner cap tapers in cross-sectional thickness, thebase of said inner cap thicker than the rim of said inner cap.

Preferably said outer cap is of uniform cross-sectional thickness.

Alternatively said outer cap tapers in cross-sectional thickness, thebase of said outer cap thicker than the rim of said outer cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk,    -   said cap section formed from an inner air delivery tube having        substantially parallel inner walls that substantially align with        the inner wall of said stalk so that said inner air deliver tube        extends upwards from the top of said stalk, and an outer cap        which surrounds and extends above the top of said inner air        delivery tube in such a manner that there is an air gap between        said inner air delivery tube and said outer cap, said outer cap        having a bead which is formed on and extends substantially        inward from the rim of said outer cap.

Preferably said air delivery tube tapers in cross-sectional thickness,the inner wall of said air deliver tube having parallel sides, the outersides tapering inwards towards the top of said air delivery tube.

Preferably said outer cap has a uniform cross-sectional thickness.

Preferably said bead extends inwards from and around said rim of saidouter cap, around the entire perimeter of said outer cap.

Preferably bead is thicker in cross-section than the cross-sectionalthickness of said outer cap or air delivery tube or both.

Preferably said bead has a uniform cross-sectional thickness.

Alternatively said bead varies in cross-sectional thickness around theperimeter of said cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap, the outer surface of said        outer cap adapted to substantially seal against the nare of said        user, said cap and stalk forming an airway that acts as a path        for said stream of gases to flow through said pillow portion to        said user,    -   said pillow section having at least one rib which extends across        said airgap between said inner and outer caps, said at least one        rib aligned substantially radially.

Preferably said pillow section has a series of ribs, spaced atsubstantially even or equal distances around said cap.

More preferably said pillow section has four ribs, said ribs spacedaround said cap at substantially 90-degree intervals.

Alternatively said pillow section has a pair of ribs extending acrosssaid airgap and aligned substantially radially, each of said ribs angledtowards the inner side or user side of said pillow section.

Preferably one of said ribs is aligned so that one of said ribs is alsoangled slightly inwards towards the centreline of said pillow section,and the other of said ribs is also angled outwards away from saidcentreline towards the outer side of said pillow section.

Alternatively said pillow section has two ribs that extend across saidairgap, said ribs aligned such that said ribs are substantially 180degrees apart or aligned diametrically across said airgap.

In a further alternative said pillow section has three ribs spaced atsubstantially even or equal distances around said cap, spaced aroundsaid cap at substantially 60-degree intervals.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said pillow gasket,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap and extending above said        inner cap, the outer surface of    -   said outer cap adapted to substantially seal against the nare of        said user, said cap and stalk forming an airway that acts as a        path for said stream of gases to flow through said pillow        portion to said user, said outer cap having at least one partial        rib and more preferably multiple partial ribs extending inward        toward said inner cap from said outer cap, and running from the        top edge or rim of said outer cap downwards along the surface of        the inside wall of said outer cap, said partial rib or partial        ribs extending partway from said top edge to the base of said        outer cap.

Preferably said pillow section has multiple partial ribs, each of saidpartial ribs having the same height as each of the other partial ribs.

Alternatively said pillow section has multiple partial ribs, at leastone of said partial ribs having a different height to the others.

Preferably said pillow section has multiple partial ribs, each of saidpartial ribs having the same thickness as each of the other partialribs.

Alternatively said pillow section has multiple partial ribs, at leastone of said partial ribs having a different thickness to the others.

Preferably said partial rib or partial ribs extends from said top edgeor rim downwards for substantially one fifth of the height of said outercap.

Preferably said rib is substantially circular in cross section and hasrounded edges that blend into said inside wall of said outer cap.

Preferably said at least one partial rib has a thicker centre than outerextremes.

Preferably the wall of said inner cap and the wall of said outer captaper in cross sectional thickness, being thicker at their base than atthe top or upper edge or rim.

Alternatively the wall of said inner cap and the wall of said outer caphave a constant cross-sectional thickness.

Preferably said pillow section has a pair of identical partial ribs,spaced at substantially 180 degrees from each other on the perimeter ofsaid outer cap.

In a still further aspect the invention consists in a nasal pillowsection for use as part of a system for delivering a stream of gases toa user, said system of the type that has a gases supply that produces astream of gases, a supply conduit that is connected to said gases supplyand which receives said stream of gases from said gases supply, and apatient interface connected to and in fluid communication with saidsupply conduit and adapted to deliver said stream of gases to said uservia the nares, said pillow section forming part of said patientinterface, said pillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap and extending above said        inner cap, the outer surface of said outer cap adapted to        substantially seal against the nare of said user, said cap and        stalk forming a path for said stream of gases,    -   a fin aligned radially across said pillow portion, said fin        having side portions that extend from the bottom of said air gap        at radially opposed sides of said pillow portion, up to the rim        or top of said outer cap and the rim or top of said inner cap,        and a central portion that extends across the width of said        pillow portion between said side portions, said central portion        extending from the top edge or rim of said inner cap to the top        edge or rim of outer pillow, said fin formed integrally with the        material of said inner and outer caps.

Preferably said fin has a uniform cross-sectional thickness.

Alternatively said fin tapers in cross-sectional thickness, said finthicker at the lower end at the base of said outer cap than at the upperend.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap section, said cap section connected to the upper end        of said stalk, said cap formed from an inner cap and an outer        cap, said inner cap and said outer cap arranged substantially        concentrically and separated by an air gap when not in use, said        outer cap surrounding said inner cap and extending above said        inner cap, the outer surface of said outer cap adapted to        substantially seal against the nare of said user, said inner and        outer caps and said stalk forming an airway that acts as a path        for said stream of gases to flow through said pillow portion to        said user,    -   each of said pillow portions having at least one fin that        extends diametrically across said pillow portion, said fin        having a top edge or surface that is substantially aligned with        the top edge or rim of said outer pillow, and a lower edge or        surface that is substantially aligned with the top edge or rim        of said inner cap.

Preferably said fin has a uniform cross-sectional thickness.

Alternatively said fin tapers in cross-sectional thickness, said finthicker at said lower edge or surface than at said upper edge orsurface.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   said cap including at least one partial rib extending inward        from the inside surface of the cap, and also extending downwards        from the top edge or rim of said cap along the inside surface of        said cap, said rib or ribs extending partway down the height of        said cap from said top edge towards the base of said cap.

Preferably said pillow section has multiple partial ribs, each of saidpartial ribs having the same height or length as each of the otherpartial ribs.

Preferably said pillow section has multiple partial ribs, at least oneof said partial ribs having a different height or length to the others.

Preferably said nasal pillow section has multiple partial ribs, each ofsaid partial ribs having the same cross-sectional thickness as eachother of said partial ribs.

Preferably said nasal pillow section has multiple partial ribs, at leastone of said partial ribs having a different cross-sectional thickness tothe other partial ribs.

Preferably said partial rib is curved from top to bottom along theinside edge of said rib.

Preferably each one of said partial rib or ribs has a greatercross-sectional thickness at the top of the rib and tapers or curves insuch a manner that said partial rib merges with the wall of said pillowportion at the bottom of said rib.

More preferably each one of said partial rib or ribs extends from thetop edge or rim of said downwards for substantially one third of theheight of said cap.

Preferably said pillow section has two partial ribs diametricallyopposed on the perimeter of said cap.

Even more preferably said cap wall is tapered in thickness, said capwall being thicker at the base of said cap and thinner at the rim ofsaid cap.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   said cap including at least one but preferably a series of ribs        extending inward from the inner surface of said cap, and        extending from a point at or close to the top edge or rim of        said cap and a point at or close to the base of said cap.

Preferably said pillow section has multiple ribs, at least one of saidribs having a different cross-sectional thickness to the others of saidribs.

Preferably said rib or ribs follow the contour of the inside surface ofsaid cap wall, the top end and lower end of said rib curved towards theinner surface so as to blend with the inner surface of said cap, thecross-sectional thickness of said rib greatest at the centre of saidrib.

Preferably said rib or ribs follow the contour of the inside surface ofsaid cap wall, said rib having a constant cross-sectional thicknessalong its entire height or profile.

Alternatively said pillow section has a plurality of ribs, said ribshaving the same cross-sectional thickness as each other.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   said cap further comprising a fin, said fin aligned        substantially diametrically across said cap, the top edge of        said fin extending downwards from a position at or close to the        top edge or rim of said cap to substantially three quarters of        the way down the height of said cap.

In one form said fin has a uniform cross-sectional thickness or width atany position over the height of said fin.

In another form said fin tapers in width, said fin thicker at each endtowards the inner surface of the wall of said cap than in the centre.

In a further form said fin tapers in thickness over the height of saidfin, said fin having a base or lower end which is thicker than the upperend or top.

Preferably the bottom edge of said fin is curved upwards.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   said cap having at least one bead which extends outwards from        the outer surface of said cap, and which extends around the        perimeter of said cap.

Preferably said bead extends in a substantially unbroken ring around theperimeter of said cap.

Preferably said bead is located at or close to the rim of said cap.

Preferably said bead is substantially semi-circular in cross section.

Preferably said bead is of uniform thickness along the entire perimeterof said cap.

Alternatively said bead differs in thickness at various points along theperimeter of said cap.

More preferably said bead is twice as thick as said cap wall.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   said cap having a top edge or rim which in use is inserted into        the nostril of a user, said top edge or rim having a greater        cross-sectional thickness than at least the centre portion of        said cap.

Preferably said top edge or rim is formed from the upper one fifth ofsaid cap.

More preferably the cross-section of said cap is uniform, except forsaid top edge or rim.

Preferably the base of said cap has substantially the same thickness assaid top edge or rim, and the middle or centre portion of said cap wallbetween said base and said top edge or rim is thinner than said top edgeor rim and said base.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   a gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   a pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   said cap having a first bead which extends inward from the inner        surface of the wall of said cap, said cap having an open top and        a rim which forms the perimeter of said open top, said first        bead located at or close to the open top of said cap, said first        bead hemispherical or semi-circular in cross-section.

Preferably said first bead has a cross-sectional thickness greater thanthe cross-sectional thickness of said wall of said cap.

Preferably the cross-sectional thickness of said first bead issubstantially double that of said wall.

Preferably said first bead forms a substantially unbroken ring aroundthe inner surface of said wall.

More preferably said first bead has a substantially uniform crosssectional thickness.

Preferably said first bead is located at the same vertical position atall points around the perimeter.

Alternatively the vertical position of said first bead may vary aroundsaid perimeter.

Preferably said cap has a second, lower bead located below said firstbead, said lower bead extending inwards from the inner surface of saidwall.

More preferably said lower bead is disposed between 2 and 25 mm belowsaid first bead.

Preferably said lower bead has a cross-sectional thickness greater thanthe cross-sectional thickness of said wall of said cap.

More preferably the cross-sectional thickness of said lower bead issubstantially double that of said wall.

Preferably said lower bead forms a substantially unbroken ring aroundthe inner surface of said wall.

Preferably said lower bead has a substantially uniform cross sectionalthickness.

Preferably said lower bead is located at the same vertical position atall points around the perimeter.

Alternatively the vertical position of said lower bead may vary aroundsaid perimeter.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        said cap formed from an inner cap and an outer cap, said inner        cap and said outer cap arranged substantially concentrically and        separated by an air gap when not in use, said outer cap        surrounding said inner cap, the outer surface of said outer cap        adapted to substantially seal against the nare of said user,        said caps and said stalk forming an airway that acts as a path        for said stream of gases to flow through said pillow section and        to said user,    -   aid inner cap having an upper opening, and a bead which extends        outwards from the outer wall of said inner cap at or close to        the rim of said inner cap,    -   aid inner cap further having at least one and preferably a        plurality of openings which pass through the wall of said inner        cap.

Preferably said bead forms a continuous ring.

Preferably said bead is semi-circular in cross section and of constantcross sectional thickness all the way around said inner cap.

Preferably said inner cap has four openings.

Preferably said openings are circular.

Preferably said openings are spaced at regular intervals around theouter surface of said inner cap.

Preferably wherein said inner cap further comprises at least one ribextending outward from the outer surface of said inner cap.

More preferably said inner cap further comprises a plurality of ribsarranged around the outer surface of said inner cap extending outwards.

Preferably said rib or ribs are rectangular in cross-section.

Preferably said rib or ribs are curved in cross-section.

Preferably said rib or ribs are twice the thickness of the wall of saidouter cap.

Preferably said rib or ribs are placed at regular intervals around theouter surface of said inner cap.

More preferably said ribs are positioned between successive ones of saidopenings.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   said stalk also having at least one rib which extends outwards        from the outer surface of said stalk.

Preferably said rib or ribs extend outwards substantially perpendicularto the body of said stalk, from substantially the midpoint of saidstalk.

Preferably each of said rib or ribs is an elongate member with a roundedouter end.

Preferably said at least one rib is a pair of ribs at substantiallydiametrically opposed positions on said stalk.

Preferably said stalk is longer than the height of said rib or ribs.

Preferably the base of said cap is wider than the length of said rib orribs.

In another form said ribs extend outwards from the base of the stalk.

Preferably said ribs extend upward for substantially one-third of theheight of the stalk.

Preferably said ribs are a pair of ribs, the outer edge of one of theribs curving away from the centre of said stalk, the outer edge of theother of said ribs curving toward the centre of the stalk.

In a further alternative form said ribs extend outwards from the top ofthe stalk, directly underneath the base of said cap.

Preferably said ribs extend downward from the top of said stalk forsubstantially one-half of the height of the stalk.

Preferably said rib or ribs extend outwards substantially perpendicularto the body of said stalk.

Preferably each of said rib or ribs is an elongate member with a roundedouter end.

Preferably said at least one rib is a pair of ribs at substantiallydiametrically opposed positions on said stalk.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   aid stalk also having at least one rib which extends outwards        from the outer surface of said stalk, said rib substantially        curved away from the centre of said stalk.

Preferably said rib has a planar outer face and concave sides.

Preferably said stalk has four ribs arranged at equal intervals aroundperimeter of said stalk.

Preferably the base of said cap extends outwards further from the sidesof said stalk than said ribs.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   aid stalk also having at least one rib which extends outwards        from the outer surface of said stalk, said rib or ribs extending        in a spiral or helical shape around the outer surface of said        stalk.

Preferably said rib is at a helical angle suitable to allow said stalkto rotate when loaded.

Preferably said ribs are arranged at equal intervals around theperimeter of said stalk.

Preferably said ribs on each of said pillow portions spiral in oppositedirections.

Preferably the helical angle of each of said ribs is the same betweenseparate ribs.

Preferably said nasal pillow section has three ribs on each of saidpillow portions.

Preferably said ribs extend from the top of said stalk to the base ofsaid stalk.

Alternatively said ribs extend from the top of said stalk to a positionsubstantially halfway down said stalk.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        base section, the bottom of said base section connected to said        gasket portion so that gases can pass from said gasket portion        into said base section, and a cap, the bottom end of said cap        connected to the upper end of said base section, the outer        surface of said cap adapted to substantially seal against the        nare or nostril of said user, said base section and said cap        forming a gases path for said stream of gases to flow to said        user,    -   aid base section extending directly from said gasket portion,        said upper end of said base section at least as wide as said        bottom end of said cap, said cap extending upwards from said        upper end of said base section, said cap substantially funnel        shaped, narrowing from said bottom end of said cap.

Preferably said gases path through said base section and said cap is aswide as possible through said base section and at the point of entry tosaid cap.

Preferably said base section is formed in such a manner that said basesection has substantially less flexibility than said cap, said basesection shaped and arranged such that said cap deforms downward towardsaid base section when loaded.

Preferably the wall of said base section is of greater thickness thanthe wall of said cap.

Preferably the side walls of said base section are substantiallystraight and extend upwards substantially perpendicularly from the uppersurface of said gasket.

Alternatively the side walls of said base section are tapered inwardstowards each other from the top of the base section so that the bottomof said base section is narrower than the top of said base section, suchthat said gases path widens from the bottom of the base section towardsthe top.

In a further alternative form the side walls of said base section extendupwards from the gasket portion substantially parallel to each other,curving outwards before connecting to the cap so that said pillowportion has a central bulge where the base section and the cap connect.

In another alternative form the side walls of said base section taper orangle inwards towards each other, so that said bottom of said basesection is wider than said bottom end of said cap, the sides of saidbase section angled outward such that the lower portion of the basesection is wider than the upper portion of said base section.

In another alternative form said base section is wider at the centralportion of said base section than at the upper and lower ends, the wallsof said base section rounded outwards between said bottom of said basesection and said bottom end of said cap.

Preferably the wall thickness of said base section is substantiallyconstant over the height of said base section, so that said air paththrough said base section is substantially defined by the contours ofthe walls of said base section.

Preferably said base section has at least one rib extending inwardsubstantially radially from the inner wall of said base section towardthe centre of the said base section.

More preferably said at least one rib extends between the bottom of saidbase section and a point just above the bottom of the cap.

Further said at least one rib curves inwards towards the central axis ofthe pillow portion.

Further the maximum inwards extent of said at least one rib is theperimeter of a circle defined by looking straight down the axis of thepillow portion from the top opening of the cap from above.

Preferably said ribs are twice the thickness of the wall of said cap.

Preferably said at least one rib is four ribs spaced at equal intervalsaround the inner surface of the wall of said pillow portion andextending inwards substantially radially.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        base section, the bottom of said base section connected to said        gasket portion so that gases can pass from said gasket portion        into said base section, an intermediate section on the top of        said base section extending upwards, and a cap located above        said base section and said intermediate section, the outer        surface of said cap adapted to substantially seal against the        nare or nostril of said user, said base section, said        intermediate section and said cap forming a gases path for said        stream of gases to flow to said user,    -   the bottom of said cap fitting inside the intermediate portion        so that the intermediate portion generally forms a boundary wall        around the top of said base portion, said bottom of said cap        fitting inside said boundary wall, said cap extending upwards        above said boundary wall.

Preferably said boundary wall is formed in such a manner that it issubstantially flexible and can deform to conform with the shape of auser's nose and form an effective seal.

In a further aspect the invention consists in a nasal pillow section foruse as part of a system for delivering a stream of gases to a user, saidsystem of the type that has a gases supply that produces a stream ofgases, a supply conduit that is connected to said gases supply and whichreceives said stream of gases from said gases supply, and a patientinterface connected to and in fluid communication with said supplyconduit and adapted to deliver said stream of gases to said user via thenares, said pillow section forming part of said patient interface, saidpillow section comprising:

-   -   gasket portion, adapted to receive said stream of gases from        said supply conduit,    -   pair of pillow portions connected to and extending from said        gasket portion, said pillow portions adapted to receive said        stream of gases from said gasket portion and provide said stream        of gases to said user, each of said pillow portions having a        stalk, the base of said stalk connected to said gasket portion,        and a cap, said cap connected to the upper end of said stalk,        the outer surface of said cap adapted to substantially seal        against the nare of said user, said caps and said stalk forming        an airway that acts as a path for said stream of gases to flow        through said pillow portion to said user,    -   said cap having a flange portion around the lower part of said        cap, said flange portion sloping downwards and outwards to        surround the upper part of the stalk, said flange portion        substantially flexible.

Preferably said pillow section also has at least one rib, runningbetween the outer surface of said stalk and the underside of saidflange, said at least one rib adapted to support said flange.

More preferably said at least one rib is four ribs arranged around saidflange portion and running radially outwards from the outer surface ofsaid stalk.

Preferably the lower edge or surface of said rib or ribs does not extenddownwards further than the lower edge of said flange.

Preferably the inside walls of said pillow portion are parallel to eachother forming a smooth vertical airway.

Preferably said cap section has an internal cavity with a greater widththan the internal width or diameter of said stalk.

To those skilled in the art to which the invention relates, many changesin construction and widely differing embodiments and applications of theinvention will suggest themselves without departing from the scope ofthe invention as defined in the appended claims. The disclosures and thedescriptions herein are purely illustrative and are not intended to bein any sense limiting.

The invention consists in the foregoing and also envisages constructionsof which the following gives examples.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described withreference to the accompanying drawings.

FIG. 1 shows a schematic view of a system for supplying a stream ofheated humidified gases to a user via an interface assembly, the systemincluding a gases supply unit or blower, a humidifier chamber gaseouslyor fluidically connected to the gases supply unit, and a supply conduitconnecting the humidifier chamber to an interface assembly.

FIG. 2a shows a perspective view from the front and to one side of afirst preferred embodiment of the interface assembly of the presentinvention, showing an interface core portion or core section adapted toconnect to the supply conduit so the interface can receive gases fromthe gases supply unit in use, a nasal pillow section also included aspart of the interface core section, and a headgear assembly connected tothe core section which is adapted to hold the interface in position onthe head of a user.

FIG. 2b shows the interface of FIG. 2a in use, being worn by a user,viewed from the same angle as FIG. 2 a.

FIG. 2c shows an exploded view of the interface of FIG. 2a or 2 b.

FIG. 2d shows a first preferred form of nasal pillow section for use aspart of the first preferred embodiment of patient interface assembly,the nasal pillow section comprising a pair of pillow portions connectedto a pillow gasket portion.

FIG. 3a shows a second preferred embodiment of the interface assembly ofthe present invention, the second preferred embodiment containingsimilar elements to those of the first preferred form of FIG. 2 butconfigured differently.

FIG. 3b shows the functionality of the connection between the supplyconduit and the interface core section of the second preferredembodiment of FIG. 3 a.

FIG. 3c shows a close-up view of the interface core portion or coresection of FIG. 3 a.

FIG. 4a shows a third preferred embodiment of the interface assembly ofthe present invention being worn by a user, the interface assembly ofthis third preferred form having similar elements to those of thepreferred embodiments of FIGS. 2 and 3, but configured differently.

FIG. 4b shows an exploded perspective view of the interface of FIG. 4 a.

FIG. 5a shows a top view of the first preferred embodiment of nasalpillow section, the nasal pillow section comprising a pair of pillowportions connected to a pillow gasket portion with internal hiddendetail including internal ribs of the pillow portions shown, and sectionlines X and Y which bisect each of the pillows also shown, section lineY bisecting the pillows and the ribs within the pillows, and sectionline X bisecting the pillows to one side of the ribs.

FIG. 5b shows a view of the nasal pillow section of FIG. 5a from thepoint of view of a user, each of the nasal pillow portions shown incross-section, the cross-section for each pillow portion taken along thesection lines X and Y, the cross-section showing internal detail of thestructure of each of the nasal pillow portions.

FIG. 5c shows a detail view of the right-hand nasal pillow of FIG. 5 b.

FIG. 6a shows a top view of an alternative embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal hidden detailincluding internal ribs of the pillow portions shown, and section linesX and Y which bisect each of the pillows also shown, section line Ybisecting the pillows and the ribs within the pillows, and section lineX bisecting the pillows to one side of the ribs.

FIG. 6b shows a view of the nasal pillow section of FIG. 6a from thepoint of view of a user, each of the nasal pillow portions shown incross-section, the cross-section for each pillow portion taken along thesection lines X and Y, the cross-section showing internal detail of thestructure of each of the nasal pillow portions.

FIG. 6c shows a detail view of the right hand nasal pillow of FIG. 6 b.

FIG. 7a shows a top view of a further alternative embodiment of nasalpillow section, the nasal pillow section comprising a pair of pillowportions connected to a pillow gasket portion with internal hiddendetail including internal ribs of the pillow portions shown, and sectionlines X and Y which bisect each of the pillows also shown, section lineY bisecting the pillows and the ribs within the pillows, and sectionline X bisecting the pillows to one side of the ribs.

FIG. 7b shows a view of the nasal pillow section of FIG. 5a from thepoint of view of a user, each of the nasal pillow portions shown incross-section, the cross-section for each pillow portion taken along thesection lines X and Y, the cross-section showing internal detail of thestructure of each of the nasal pillow portions.

FIG. 7c shows a detail view of the right hand nasal pillow of FIG. 7 b.

FIG. 8a shows a top view of yet another embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal hidden detailincluding internal ribs of the pillow portions shown, and section linesX and Y which bisect each of the pillows also shown, section line Xbisecting the pillows and the ribs within the pillows, and section lineY bisecting the pillows to one side of the ribs.

FIG. 8b shows a view of the nasal pillow section of FIG. 8a from thepoint of view of a user, each of the nasal pillow portions shown incross-section, the cross-section for each pillow portion taken along thesection lines X and Y, the cross-section showing internal detail of thestructure of each of the nasal pillow portions.

FIG. 8c shows a detail view of the right hand nasal pillow of FIG. 8 b.

FIG. 9a shows a top view of a still further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal hidden detailincluding internal ribs of the pillow portions shown, and section linesX and Y which bisect each of the pillows also shown, section line Xbisecting the pillows and the ribs within the pillows, and section lineY bisecting the pillows to one side of the ribs.

FIG. 9b shows a view of the nasal pillow section of FIG. 9a from thepoint of view of a user, each of the nasal pillow portions shown incross-section, the cross-section for each pillow portion taken along thesection lines X and Y, the cross-section showing internal detail of thestructure of each of the nasal pillow portions.

FIG. 9c shows a detail view of the right hand nasal pillow of FIG. 9 b.

FIG. 10a shows a top view of a still further embodiment of the nasalpillow section, the nasal pillow section comprising a pair of pillowportions connected to a pillow gasket portion with internal hiddendetail including an internal solid fin within each of the pillowportions shown, and section lines X and Y which bisect each of thepillows also shown, section line X bisecting the pillows and the finwithin one of the pillows, and section line Y bisecting the other of thepillows to one side of the fin.

FIG. 10b shows a view of the nasal pillow section of FIG. 10a from thepoint of view of a user or patient, each of the nasal pillow portionsshown in cross-section, the cross-sectional view for each pillow portiontaken along the section lines X and Y, the cross section showing theinternal detail of the structure of each of the pillow portions.

FIG. 10c shows a detail view of the right hand nasal pillow of FIG. 10b, bisected by section line Y.

FIG. 11a shows a top view of a still further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal hidden detailincluding internal ribs of the pillow portions shown, and section linesX and Y which bisect each of the pillow portions also shown, sectionline X bisecting the ribs within one of the pillow sections, and sectionline Y bisecting the other pillow section to one side of the ribs.

FIG. 11b shows a view of the nasal pillow section of FIG. 11a from thepoint of view of a user, each of the nasal pillow portions shown incross-section, the cross-section for each pillow portion taken along thesection lines X and Y, the cross-section showing internal detail of thestructure of each of the nasal pillow portions, including the ribs.

FIG. 11c shows a detail view of the right hand nasal pillow portion ofFIG. 11b showing detail of the rib or ribs.

FIG. 12 shows a detail view of a further embodiment of a nasal pillowportion in cross-section, the pillow portion comprising a stalk, anouter cap and an inner cap, the inner cap thicker at the rim and thinnerat the base.

FIG. 13 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, the inner cap wall tapering in thicknesssuch that the wall is thicker at the base than at the rim, a first beadextending inwards from the top edge or rim of the inner cap and a secondbead extending inwards from the top edge or rim of the outer cap.

FIG. 14 shows a detail view of a still further embodiment of a nasalpillow portion in cross section, the pillow portion comprising a stalk,an outer cap and an inner cap, the pillow portion also comprising asmall flange which extends upwards from between the join of the outerand inner cap.

FIG. 15 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, the inner cap and outer cap walls of uniform(but different) thicknesses, a first bead extending inwards from the topedge or rim of the inner cap and a second bead extending inwards fromthe top edge or rim of the outer cap, the beads extending around theperimeter of their respective caps.

FIG. 16 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, a bead extending from the inside wall of theouter cap, the bead located in the upper third of the outer cap profileand the bead extending around the perimeter of the outer cap.

FIG. 17 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, a bead extending outwards from the outerwall of the inner cap, the bead extending from the top edge or rim ofthe inner cap and around the perimeter of the inner cap.

FIG. 18 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, and a bead which extends outwards from therim of the outside wall of the outer cap, the bead extending around theperimeter of the outer cap, the inner cap wall being thicker at the baseand thinner at the rim.

FIG. 19 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, and a bead which extends from the outer wallof the inner cap, the bead located in the upper region of the inner capbut below the rim.

FIG. 20 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, and a bead which extends from the insidewall of the inner cap, the bead extending inwards from the rim of theinner cap and around the perimeter of the inner cap, the inner cap wallthicker than the outer cap wall.

FIG. 21 shows a detail view of a further embodiment of the nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, a bead extending from the inside wall of theouter cap, the bead extending from the rim of the outer cap and aroundthe perimeter of the outer cap, the inner cap wall thicker than theouter cap wall.

FIG. 22 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, and a bead which extends inwards from theinside wall of the inner cap, the bead extending from the rim and aroundthe perimeter of the cap, the inner cap wall tapering in thickness, andbeing thicker at the base than at the rim.

FIG. 23 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, the pillow portion also comprising a beadwhich extends inwards from the inside wall of the outer cap, the beadextending from the rim of the outer cap and around the perimeter of theouter cap, the inner cap wall tapering in thickness, and being thickerat the base than at the rim.

FIG. 24 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, the inner cap being the same height as theouter cap and the rims of the inner and outer cap being aligned in thesame plane, as shown in the figure.

FIG. 25 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk and acap, the pillow portion also comprising a slightly tapered air deliverytube within the cap, the rim of the air delivery tube in line with therim of the cap, the air delivery tube extending through the cap andthrough the stalk to form a passageway for a stream of gases to travelto the patient or user.

FIG. 26 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, the inner cap tapering in thickness so thatthe inner cap is thicker at the base and thinner at the rim, the wall ofthe outer cap being tapered in thickness and the wall of the outer capbeing thicker at the rim than at the base.

FIG. 27 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk and acap, the pillow portion also comprising an air delivery tube within thecap, the air delivery tube extending through the cap and stalk to form apassageway for a stream of gases or air to travel to a patient or userand the air delivery tube extending past the rim of the cap.

FIG. 28 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk, anouter cap and an inner cap, and the rim of the inner cap extending abovethe rim of the outer cap.

FIG. 29 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk and acap, the pillow portion also comprising a slightly tapered air deliverytube housed within the cap, the cap covering the air delivery tube, theair delivery tube extending through the stalk to form a passageway for astream of gases to travel to a patient or user, and the inside wall ofthe cap having a bead that extends inwards from the rim of the cap.

FIG. 30 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk and acap, and an air delivery tube that is housed within the cap and extendsthrough the stalk to form a passageway to deliver a stream of gases orair to a patient or user, the wall of the cap tapering in thickness sothat the wall is thicker at the base than at the rim.

FIG. 31 shows a detail view of a further embodiment of a nasal pillowportion in cross section, the pillow portion comprising a stalk and acap, and an air delivery tube that is housed within the cap and whichextends through the stalk to form a passageway to deliver a stream ofgases or air to a patient or user, the wall of the cap being uniform inthickness.

FIG. 32 shows a top view of a further embodiment of a nasal pillowsection comprising a pair of pillow portions connected to a pillowgasket portion, with internal hidden detail including internal ribs ofthe pillow portions shown, the nasal pillow portions of this embodimenthaving an inner and an outer cap, and four ribs arranged runninggenerally radially outward from a central axis and spaced equidistantaround each of the pillow portions, the ribs passing between the innerand the outer caps.

FIG. 33 shows a top view of a further embodiment of a nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion, each pillow portion having aninner and an outer cap, with internal hidden detail shown, includinginternal ribs which run between the inner and the outer caps shown, theribs running generally radially outward from a central axis, each nasalpillow section having two ribs, the two ribs arranged so that theyapproximately or roughly define a quarter-circle between the lower orinner part of the nasal pillow section and the side.

FIG. 34 shows a top view of a further embodiment of a nasal pillowsection comprising a pair of pillow portions connected to a pillowgasket portion with internal hidden detail including internal ribs ofthe pillow portions shown, the nasal pillows section having an inner capand an outer cap, with two ribs in each pillow portion running betweenthe inner and the outer caps, the ribs in each pillow section arrangeddiametrically opposite to each other.

FIG. 35 shows a top view of a further embodiment of a nasal pillowsection comprising a pair of pillow portions connected to a pillowgasket portion, each of the pillow portions having an inner cap and anouter cap, the figure also showing hidden detail of internal ribs whichrun between the inner cap and the outer cap shown, each of the nasalpillow sections having three ribs arranged radially running between theinner cap and the outer cap, and spaced generally equidistant from oneanother shown.

FIG. 36a shows a top view of a further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal hidden detailincluding internal ribs of the pillow portions shown, and section linesX and Y which bisect each of the pillows also shown, section line Xbisecting one of the pillow portions and the ribs within the pillowportion, and section line Y bisecting the other of the pillow portionsto one side of the ribs.

FIG. 36b shows a view of the nasal pillow section of FIG. 36a from thepoint of view of a user, each of the nasal pillow portions shown incross-section to show an inner cap and an outer cap, the cross-sectionfor each pillow portion taken along the section lines X and Y, thecross-section showing internal detail of the structure of each of thenasal pillow portions and showing a pair of bumps or protuberanceslocated at the top edge of the outer cap facing inwards at radiallyopposed positions.

FIG. 36c shows a detail view of the right hand nasal pillow portion ofFIG. 36 b.

FIG. 37a shows a top view of a still further embodiment of a nasalpillow section, the nasal pillow section comprising a pair of pillowportions connected to a pillow gasket portion with internal hiddendetail including an internal solid fin within each of the pillowportions shown, and section lines X and Y which bisect each of thepillows also shown, section line X bisecting one of the pillow portionsand the fin within the pillow portion, and section line Y bisecting theother pillow portion to one side of the fin.

FIG. 37b shows a view of the nasal pillow section of FIG. 37a from thepoint of view of a user or patient, each of the nasal pillow portionsshown in cross-section to show an inner cap and an outer cap, thecross-section for each pillow taken along the section line X and Y, thecross section showing the internal detail of the structure of each ofthe pillow portions.

FIG. 37c a detail view of the right hand nasal pillow portion of FIG. 37b.

FIG. 38a shows a top view of a further embodiment of a nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal hidden detailincluding an internal solid fin within each of the pillow portion shown,and section lines X and Y which bisect each of the pillows also shown,section line X bisecting one of the pillow portions and the fin withinthe pillow portion, and section line Y bisecting the other pillowportion to one side of the fin.

FIG. 38b shows a view of the nasal pillow section of FIG. 38a from thepoint of view of a user or patient, each of the nasal pillow portionsshown in cross-section to show an inner cap and an outer cap, thecross-section for each pillow taken along the section line X and Y, thecross section showing the internal detail of the structure of each ofthe pillow portions, each pillow portion having a flat fin likestructure extending upward and across the cap.

FIG. 38c a detail view of the right hand nasal pillow of FIG. 38 b.

FIG. 39a shows a top view of a further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal detail of each of thepillow portions shown, each of the pillow portions including internalribs, and section lines X and Y which bisect each of the pillow portionsalso shown, section line Y bisecting the right-hand pillow portion andthe ribs within the pillow portion, and section line X bisecting theleft-hand pillow portion to one side of the internal ribs.

FIG. 39b shows a view of the nasal pillow section of FIG. 39a from thepoint of view of a user, each of the nasal pillow portions shown incross-section, the cross-section for each pillow portion taken along thesection lines X and Y, the cross-section showing internal detail of thestructure of each of the nasal pillow portions.

FIG. 39c shows a detail view of the right hand nasal pillow of FIG. 39b, bisected by line Y.

FIG. 40a shows a top view of a further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal detail of the pillowportions shown, each of the pillow portions having internal ribs, andsection lines X and Y which bisect each of the pillows also shown,section line Y bisecting one of the pillows and the ribs within thepillow, and section line X bisecting the other of the pillows to oneside of the ribs.

FIG. 40b shows a view of the nasal pillow section of FIG. 40a from thepoint of view of a user, each of the nasal pillow portions shown incross-section, the cross-section for each pillow portion taken along thesection lines X and Y, the cross-section showing internal detail of thestructure of each of the nasal pillow portions.

FIG. 40c shows a detail view of the right hand nasal pillow of FIG. 40b, through the section line Y.

FIG. 41a shows a top view of a still further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal detail within thepillow portion shown, each of the pillow portions having an internalfin, and section lines X and Y which bisect each of the pillows alsoshown, section line X bisecting the left hand one of the pillows and thefin within the pillows, and section line Y bisecting the right handpillow to one side of the fin.

FIG. 41b shows a view of the nasal pillow section of FIG. 41a from thepoint of view of a user or patient, each of the nasal pillow portionsshown in cross-section, the cross-section for each pillow taken alongthe section lines X and Y, the cross section showing the internal detailof the structure of each of the pillow portions.

FIG. 41c shows a detail view of the right hand nasal pillow of FIG. 41balong section line Y.

FIG. 42a shows a top view of a still further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal hidden detail withineach of the pillow portions shown, each of the pillow portions having aninternal fin, and section lines X and Y which bisect each of the pillowsalso shown, section line X bisecting the left-hand pillow and the finwithin the pillows, and section line Y bisecting the right-hand pillowto one side of the fin, the figure further showing the fin being taperedin thickness, with the fin thicker at edges than in the centre.

FIG. 42b shows a view of the nasal pillow section of FIG. 42a from thepoint of view of a user or patient, each of the nasal pillow portionsshown in cross-section, the cross-section for each pillow taken alongthe section lines X and Y, the cross section showing the internal detailof the structure of each of the pillow portions.

FIG. 42c shows a detail view of the right hand nasal pillow of FIG. 42b, taken along the section line Y.

FIG. 43 shows a still further embodiment of a nasal pillow portion, thepillow portion comprising a stalk and a cap section, with a beadextending outwards from the rim of the cap section around the perimeterof the cap section.

FIG. 44 shows a still further embodiment of a nasal pillow portion, thepillow portion comprising a stalk and a cap section, the top or rim ofthe cap section wall being thicker in cross-sectional thickness thancross-sectional thickness of the middle part of the cap wall.

FIG. 45 shows a still further embodiment of a nasal pillow portion, thepillow portion comprising a stalk and a cap section, the wall of the capsection having a uniform cross section, and a bead applied to the insidesurface of the cap section and extending inwards and running around theperimeter of the cap section.

FIG. 46 shows a still further embodiment of a nasal pillow portion, thepillow portion comprising a stalk and a cap section, the cap wall havinga uniform cross sectional thickness, the cap section having two beadsapplied to the inside surface of the cap, at least one of the beadsextending inwards from the rim of the cap and the other of the beadsextending inwards from the wall of the cap section below the first bead,the beads extending around the perimeter of the cap.

FIG. 47a shows a top view of a still further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal detail also shown,each of the pillow portions having a cap section that consists of aninner and an outer cap separated by an air gap, the inner cap having abead around the rim extending outwards, and a series of holes passingthrough the wall of the inner cap, a pair of section lines X and Y foreach of the pillow portions also shown.

FIG. 47b shows a view of the nasal pillow section of FIG. 47a from thepoint of view of a user or patient, each of the nasal pillow portionsshown in cross-section, the cross-section for each pillow taken alongthe section lines X and Y, the cross section showing the internal detailof the structure of each of the pillow portions.

FIG. 47c shows a detail view of the right hand nasal pillow of FIG. 47b.

FIG. 48a shows a top view of a still further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal detail also shown,each of the pillow portions having a cap section that consists of aninner and an outer cap separated by an air gap, the inner cap having abead around the rim extending outwards, and a series of holes passingthrough the wall of the inner cap, each of the pillow sections alsohaving a number of ribs passing between the inner and outer caps withinthe air gap, a pair of section lines X and Y for each of the pillowportions also shown.

FIG. 48b shows the nasal pillow section of FIG. 48a from the point ofview of a user or patient, each of the nasal pillow portions shown incross-section, the cross-section for each pillow taken along the sectionlines X and Y, the cross section showing the internal detail of thestructure of each of the pillow portions.

FIG. 48c shows a detail view of the right hand nasal pillow of FIG. 47b.

FIG. 49a shows a top view of a still further embodiment of nasal pillowsection, the nasal pillow section comprising a pair of pillow portionsconnected to a pillow gasket portion with internal detail also shown,each of the pillow portions having a cap section that consists of aninner and an outer cap separated by an air gap, the inner cap having abead around the rim extending outwards, and a series of holes passingthrough the wall of the inner cap, each of the pillow sections alsohaving a number of ribs passing between the inner and outer caps withinthe air gap, the ribs as being curved in profile, and a pair of sectionlines X and Y for each of the pillow portions also shown.

FIG. 49b shows the nasal pillow section of FIG. 49a from the point ofview of a user or patient, each of the nasal pillow portions shown incross-section, the cross-section for each pillow taken along the sectionlines X and Y, the cross section showing the internal detail of thestructure of each of the pillow portions.

FIG. 49c shows a detail view of the right hand nasal pillow of FIG. 47b.

FIG. 50a shows a user or rear view of a still further embodiment ofnasal pillow section, the nasal pillow section comprising a pair ofpillow portions connected to a pillow gasket portion, each of the pillowportions comprising a stalk and a cap, the stalk having a series of ribsextending outwards from the outer surface of the stalk, the ribs locatedat regular intervals around the perimeter of the stalk, a pair ofsection lines X and Y which bisect each of the stalks perpendicular tothe main axis of the stalk also shown, section line X bisecting the lefthand one of the stalks through the ribs on the stalk, section line Ybisecting the stalk below the ribs on the stalk.

FIG. 50b shows a view of the stalks of FIG. 50a through the crosssections along the lines X and Y looking upwards towards the top of thepillow portions.

FIG. 50c shows a detail view of the right hand pillow portion of FIG. 50a.

FIG. 51a shows a user or rear view of a still further embodiment ofnasal pillow section, the nasal pillow section comprising a pair ofpillow portions connected to a pillow gasket portion, each of the pillowportions comprising a stalk and a cap, the stalk having a series of ribsextending outwards from the outer surface of the stalk at or close tothe base of the stalk, the ribs located at regular intervals around theperimeter of the stalk, a pair of section lines X and Y which bisecteach of the stalks perpendicular to the main axis of the stalk alsoshown, section line X bisecting the left hand one of the stalks, sectionline Y bisecting the right-hand one of the stalks, the ribs generallyextending upwards from the base of each of the stalk to approximatelymidway up each of the stalks.

FIG. 51b shows a view of the stalks of FIG. 51a through the sectionlines X and Y looking upwards towards the top of the pillow portions.

FIG. 51c shows a detail view of the right hand pillow portion of FIG. 51a.

FIG. 52a shows a user or rear view of a still further embodiment ofnasal pillow section, the nasal pillow section comprising a pair ofpillow portions connected to a pillow gasket portion, each of the pillowportions comprising a stalk and a cap, the stalk having a series of ribsextending outwards from the outer surface of the stalk at or close tothe top of the stalk, the ribs located at regular intervals around theperimeter of the stalk, a pair of section lines X and Y which bisecteach of the stalks perpendicular to the main axis of the stalk alsoshown, section line X bisecting the left hand one of the stalks, sectionline Y bisecting the right-hand one of the stalks, the ribs generallyextending downwards from the top of each of the stalk to approximatelythe mid point of each of the stalks.

FIG. 52b shows a view of the stalks of FIG. 52a through the sectionlines X and Y looking upwards towards the top of the pillow portions.

FIG. 52c shows a detail view of the right hand pillow portion of FIG. 52a.

FIG. 53a shows a user or rear view of a still further embodiment ofnasal pillow section, the nasal pillow section comprising a pair ofpillow portions connected to a pillow gasket portion, each of the pillowportions comprising a stalk and a cap, the stalks generally curving andthe ribs extending outward from the stalk and generally substantiallyidentical to each of the other ribs in thickness and shape, the ribs alllocated at regular intervals around the perimeter of the stalk, the ribsextending from the lower edge of the cap to the base of the stalk theribs curved in the horizontal plane, section lines X and Y which bisecteach of the stalks also shown, section line X bisecting the left-handstalk and ribs, and section line Y bisecting the right hand stalk andribs.

FIG. 53b shows a view of the nasal pillow section of FIG. 53a along thelines X and Y looking upwards towards the top of the pillow portions.

FIG. 53c shows a detail view of the right hand pillow portion of FIG. 53a.

FIG. 54a shows a user or rear view of a still further embodiment ofnasal pillow section, the nasal pillow section comprising a pair ofpillow portions connected to a pillow gasket portion, each of the pillowportions comprising a stalk and a cap, the stalk having a series of ribsextending outwards from the stalk and spiraling around the stalk, theribs extending from the top of the stalk to the base, a pair of sectionlines X and Y which bisect each of the stalks perpendicular to the mainaxis of the stalk also shown.

FIG. 54b shows a view of the nasal pillow section of FIG. 54a along thelines X and Y looking upwards towards the top of the pillow portions.

FIG. 54c shows a detail view of the right hand pillow portion of FIG. 54a.

FIG. 55a shows a user or rear view of a still further embodiment ofnasal pillow section, the nasal pillow section comprising a pair ofpillow portions connected to a pillow gasket portion, each of the pillowportions comprising a stalk and a cap, the stalk having a series of ribsextending outwards from the stalk and spiralling around the stalk, theribs extending from the top of the stalk but not extending all the wayto the base of the stalk, a pair of section lines X and Y which bisecteach of the stalks perpendicular to the main axis of the stalk alsoshown, section line X bisecting the left-hand stalk through the ribs andsection line Y bisecting the right-hand stalk below the bottom of theribs.

FIG. 55b shows a view of the nasal pillow section of FIG. 55a along thelines X and Y looking upwards towards the top of the pillow portions.

FIG. 55c shows a detail view of the right hand pillow portion of FIG. 55a.

FIG. 56a shows a user or rear view of a still further embodiment ofnasal pillow section, the nasal pillow section comprising a pair ofnasal pillow portions connected to a nasal gasket portion, the pillowportions having a wide base section with parallel sides and a narrow capsection so that each of the pillow portions generally has a bottle neckshape, the pillow portions in this figure shown in an undepressedposition.

FIG. 56b shows a view of the nasal pillow section of FIG. 56a with thepillow portions depressed or pressed inwards along their main axistowards the gasket portion, the upper bottleneck section deformingdownward due to the width of the base section.

FIG. 56c shows a detail view of one of the pillow sections of FIG. 56a ,in an undepressed state.

FIG. 57a shows a user or rear view of a still further embodiment ofnasal pillow section, similar to that shown in FIGS. 56a-56c , exceptthat in this variation the base section is slightly tapered inwardstowards the point of connection with the gasket portion.

FIG. 57b shows a detailed view of the pillow portion of FIG. 57 a.

FIG. 58a shows a user or rear view of a still further embodiment ofnasal pillow section, similar to that shown in FIGS. 56a-56c , exceptthat in this variation the base section is tapered or angled inwards atthe top, the tapered portion changing to a parallel sided portionapproximately halfway along the base section.

FIG. 58b shows a detail view of the stalk and cap from FIG. 58 a.

FIG. 59a shows a user or rear view of a still further embodiment ofnasal pillow section, similar to that shown in FIGS. 56a-56c , exceptthat in this variation the base section is tapered or angled outwards sothat the base section is wider at the point of connection to the nasalgasket portion than at the top.

FIG. 59b shows a detail view of one cap from FIG. 59 a.

FIG. 60a shows a user or rear view of a still further embodiment ofnasal pillow section, similar to that shown in FIGS. 56a-56c , exceptthat in this variation the walls of the base section are roundedoutwards so that the centre of the base section is wider than the ends.

FIG. 60b shows a detail view of one cap from FIG. 60 a.

FIG. 61a shows a top view of a further embodiment of the pillow sectiondescribed and shown in FIGS. 56a to 60b . The figure shows the capincluding four ribs arranged at equal intervals around the perimeter ofthe cap. Each of the ribs is of equal length. The figure shows a line Xand Y that bisects the cap. Line X bisects the cap and rib, while line Ybisects the cap to one side of the rib.

FIG. 61b shows a detail view of the embodiment of the pillow section asshown in FIG. 61a . The figure shows internal details of the cap. Therib extends from the inner wall of the cap. The rib preferably extendsfrom the base of the cap to the point where the cap begins to narrowsuddenly. The rib preferably extends inward from the cap and curvesinward toward the centre of the cap.

FIG. 62a shows a top view of a further embodiment of the pillow sectiondescribed and shown in FIGS. 56a to 60b . The figure shows the capincluding four ribs arranged at equal intervals around the perimeter ofthe cap. Each of the ribs is of equal length. The figure shows a line Xand Y that bisects the cap. Line X bisects the cap and rib, while line Ybisects the cap to one side of the rib.

FIG. 62b shows a detail view of the embodiment of the pillow section asshown in FIG. 61a . The figure shows internal details of the cap. Therib extends from the inner wall of the cap. The rib preferably extendsfrom the base of the cap to the point where the cap begins to narrowsuddenly. The rib preferably extends to form a smooth internal wallshape.

FIG. 63a shows a view of a further embodiment of the nasal pillowsection as viewed by the patient. The view shows the nasal sectioncomprising a pillow portion extending from a gasket portion. The pillowportion includes a pair of platforms extending from the gasket portionand a cap extending from each platform. The platforms are of equalheight and are substantially identical and substantially rigid. Theplatforms are of a larger diameter than the caps. The larger diameter ofthe platform adds an extra edge that acts as a secondary seal around theoutside of the patient or user's nostril. This secondary seal makes thepillow portion more adaptive and allows it be used with a variety ofnostril shapes. The platform acts as a stop and reduces the amount thecap inserts into the nostril thus increasing the size of the opening inuse, leading to reduced pressure drop across the pillow portion in use.

FIG. 63b shows a top view of the nasal pillow section of FIG. 63a . Thefigure shows the caps are angled inward toward each other.

FIG. 64a shows a view of a further embodiment of the nasal pillowsection as viewed by the patient. The view shows the nasal sectioncomprising a pillow portion extending from a gasket portion. The pillowportion includes a pair of platforms extending from the gasket portionand a cap extending from each platform. The platforms are of equalheight and are substantially identical. Preferably the platforms arepliable, meaning they are deformable. The platforms can adjust in heightwhen in use. The platforms are of a larger diameter than the caps. Thelarger diameter of the platform adds an extra edge that acts as asecondary seal around the outside of the patient or user's nostril. Thissecondary seal makes the pillow portion more adaptive and allows it beused with a variety of nostril shapes. The platform acts as a stop andreduces the amount the cap inserts into the nostril thus increasing thesize of the opening in use, leading to reduced pressure drop across thepillow portion in use.

FIG. 64b shows the top view of the embodiment of the nasal pillowsection shown in FIG. 64a . The figure shows the caps angled inwardtoward each other.

FIG. 65a shows a view of a user's nostrils from below the nostrils. Thedotted region shows the region that the platforms of either 63 a or 64 aengage with. The figure also shows the nostrils of a user are angled.

FIG. 65b shows a top view of the nasal pillow section embodiment shownin FIG. 63a or 64 a. The figure shows the dotted region occupied by theplatforms. The figure also shows how the caps are angled to fitcomplementarily within the users nostrils shown in FIG. 65 a.

FIG. 66a shows a top view of a cap of a further embodiment of the nasalpillow section. The figure does not show the gasket portion. The figureshows the pillow portion that is connected to the gasket portion. Thetop view shows the pillow portion comprising four ribs arranged aroundthe perimeter of the cap. The top view shows a line X-X that bisects thecap.

FIG. 66b shows a detail view of the nasal pillow section embodiment ofFIG. 66a . The view shows internal detail of the pillow portion shown inFIG. 66a . The figure shows a stalk with a cap extending from the stalk.The inside of the cap has an expanded area as it extends from the cap.The inside of the cap extends outward from the top of the stalk and thenextends upward and toward the centre of the cap, culminating in the exitorifice. The cap is wider than the stalk and slopes downward and outwardaround it to form a flange around the stalk. The figure shows ribsextending from the bottom of the extended cap and connecting with thestalk. The ribs add strength to the cap, minimise leakage from the capswhen in use and contribute to reducing the pressure drop across thepillow portion.

FIG. 67a shows a top view of a cap of a further embodiment of the nasalpillow section. The figure does not show the gasket portion. The figureshows the pillow portion that is connected to the gasket portion. Thetop view shows the pillow portion comprising four ribs arranged aroundthe perimeter of the cap. The top view shows a line X-X that bisects thecap.

FIG. 67b shows a detail view of the nasal pillow section embodiment ofFIG. 66a . The view shows internal detail of the pillow portion shown inFIG. 66a . The figure shows a stalk with a cap extending from the stalk.The inside of the cap extends straight upward from the top of the stalk.The inside of the cap extends to form a substantially straight airdelivery path, as seen in the figure. The cap is wider than the stalkand slopes downward and outward around it to form a flange around thestalk. The figure shows ribs extending from the bottom of the extendedcap and connecting with the stalk. The ribs add strength to the cap,minimise leakage from the caps when in use and contribute to reducingthe pressure drop across the pillow portion.

FIG. 68 is a perspective view of one embodiment of a nasal interface ofthe present invention.

FIG. 69a is an exploded view of a preferred embodiment of a nasalinterface of the present invention, showing a nasal cannula assembly anda headgear assembly which together form the nasal interface of thepreferred form of the present invention.

FIG. 69b is an exploded view of the nasal interface of FIG. 2, showing anasal cannula assembly and a headgear assembly which together form thenasal interface of one embodiment of the present invention.

FIGS. 70a and 70b are perspective views of two embodiments of a nasalcannula assembly of the present invention, the preferred form of nasalcannula assembly comprising a manifold and two nasal pillows.

FIG. 71 is a perspective view of the nasal pillow of FIG. 70a , showingdetail of a tubular base which in use is attached to the manifold, and apuff which is inserted into the nostril of a user.

FIG. 72 is an end view of the nasal pillow of FIG. 71 viewed in thedirection of arrow A.

FIG. 73a is an end view of the nasal pillow of FIG. 71 viewed in thedirection of arrow A.

FIGS. 73b to 73d are graphs showing the gradients of the nasal pillowconnecting surfaces at different cross-sections of the nasal pillow, thecross sections shown in FIG. 73 a.

FIG. 74 shows a front view of the nasal interface of the presentinvention fitted to a user, showing detail of the tubular bases of apair of nasal pillows connected to the manifold so that in use thetubular bases are parallel to one another.

FIGS. 75a to 75g show various alternative cross sections through aribbed section of the nasal pillow tubular base.

FIG. 76 shows a perspective view from the front and to one side of apreferred embodiment of the interface of the present invention, showingan interface core portion or core section that includes a pair of nasalpillows, with connecting arms extending from each side of the coreportion, a headgear connected to the connecting arms, a supply conduitconnected to the interface core portion, and a lanyard connected to thesupply conduit, the interface ready for use by a patient or user.

FIG. 77 shows a perspective view from the front and to the side of theinterface core portion of FIG. 76, showing detail of the core portionand the connecting arms, with the headgear attached.

FIG. 78a shows a perspective view from the front and slightly to oneside of the preferred form of interface core portion and connectingarms, with the nasal pillows and connecting arms connected to a gasket,the gasket, pillows and arms moulded as a one-piece item from a flexibleand supple material, and removably connected to a rigid or semi-rigidmanifold which is in use connected to the supply conduit (not shown inthis figure), the connecting arms also including removable connectortabs on the outer ends of the connecting arms which are adapted toattach the connector arms to the headgear.

FIG. 78b shows an exploded view of the preferred form of interface coreportion and connecting arms of FIG. 78 a.

FIG. 79 shows an exploded perspective view from the front and to theside of a first alternative form of interface core portion andconnecting arms, with the flexible and supple connecting arms directlyconnected or moulded to a rigid or semi-rigid manifold, the nasalpillows formed or included as part of a separate element which includesa gasket, and which is removably connected to the rigid or semi-rigidmanifold.

FIG. 80 shows an exploded perspective view from the front and to theside of a second alternative form of interface core portion andconnecting arms, with the flexible and supple nasal pillows directlyconnected or moulded to a rigid or semi-rigid manifold by way of aflexible and supple gasket, the connecting arms removably connected tothe rigid or semi-rigid manifold, or formed as part of a separateelement which is removably connected to the rigid or semi-rigidmanifold.

FIG. 81 shows a side view of the nose of a typical user, with theinterface core portion and connecting arms of the preferred embodimentlocated just below the users nose, so that they would only be requiredto be moved upwards a short distance vertically to be in an ‘in use’position, the tip or front-most portion of the users nose extendingbeyond the front-most portions of the interface core portion.

FIG. 82a shows a cut away side view of the preferred form of interfacecore portion, showing detail of the preferred form of connection betweenthe manifold and the pillows and gasket, with a lip cushion also shown.

FIG. 82b shows a cut away side view of an alternative form of interfacecore portion, showing detail of a first alternative form of connectionbetween the manifold and the pillows and gasket and the lip cushion.

FIG. 82c shows a cut away side view of another alternative form ofinterface core portion, showing detail of an air passage between theinterior of the manifold 8 and the interior of the lip cushion.

FIG. 83 shows a perspective view from the rear and to the side of thepreferred form of interface core portion, showing particular detail of alip cushion formed on the rear of the interface core portion and whichrests on the upper lip of a user in use.

FIGS. 84a to 84c show detail of different alternative forms ofconnection of the lanyard to the rest of the interface.

FIG. 85 is a mask and headgear that can be used with any of theembodiments of the nasal plugs of the present invention.

FIG. 86 is a cross-sectional view of a first form of a nasal plugs ofthe present invention.

FIG. 87 is a cross-sectional view of a second form of a nasal plugs ofthe present invention.

FIG. 88 is a cross-sectional view of a third form of a nasal plugs ofthe present invention.

FIG. 89 is a cross-sectional view of a fourth form of a nasal plugs ofthe present invention.

FIG. 90 is a cross-sectional view of a fifth form of a nasal plugs ofthe present invention.

FIG. 91 is a cross-sectional view of a sixth form of a nasal plugs ofthe present invention.

FIG. 92 is a cross-sectional view of a seventh form of a nasal plugs ofthe present invention.

FIG. 93 is a cross-sectional view of an eighth form of a nasal plugs ofthe present invention.

FIG. 94 is a cross-sectional view of a ninth form of a nasal plugs ofthe present invention.

FIG. 95 is a cross-sectional view of a tenth form of a nasal plugs ofthe present invention.

FIG. 96 is a cross-sectional view of an eleventh form of a nasal plugsof the present invention.

FIG. 97 is a cross-sectional view of a twelfth form of a nasal plugs ofthe present invention.

FIG. 98 is a cross-sectional view of the nasal plugs of FIG. 97 with adifferent coating layer.

FIG. 99 is a cross-sectional view of the nasal plugs of FIG. 97 with ayet another different coating layer.

FIG. 100 is a cross-sectional view of the nasal plugs of FIG. 98 with ayet another different coating layer.

FIG. 101 is a side view showing hidden detail of the nasal plugs of FIG.97.

FIG. 102 is a side view showing hidden detail of a thirteenth form of anasal plugs of the present invention.

FIG. 103 is a cross sectional view of the nasal plugs of FIG. 102.

FIG. 104 is a cross sectional view of the nasal plugs of FIG. 102 with adifferent coating layer.

FIG. 105 is a cross sectional view of the nasal plugs of FIG. 102 with ayet another different coating layer.

FIG. 106 is a cross sectional view of a fourteenth form of nasal plugsof the present invention.

FIG. 107 is a cross sectional view of a fifteenth form of nasal plugs ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Preferred and alternative forms of an interface for use as part of anapparatus for providing gases to a patient are described below. Thepreferred and alternative embodiments are for use as part of anapparatus for providing a stream of heated, humidified gases at apressure above atmospheric pressure to a user for the purposes of CPAPtherapy or similar.

It should be noted that the interface is not limited for use as part ofan apparatus for providing CPAP therapy. The interface could also beused for Bi-PAP or variable pressure therapy, as part of an apparatusused for an anti-snoring treatment regime, for the treatment of COPD, oras part of any therapy regime where the gases are supplied at a pressuregreater than atmospheric is delivered to the breathing passages of apatient or user via an interface assembly. Further it should be notedthat the term “patient” or “user” may be interchangeably used. They bothhave the same meaning in the context of the specification. “User” and“patient” refer to a person who will be using the system and apparatusdescribed in the specification.

The preferred embodiments will now be described in detail with referenceto the Figures. However, it should be noted that many variations arepossible which have not been specifically described, without departingfrom the intended scope.

1. Gases Supply System

FIG. 1 shows a schematic view of a typical system 1 for providing astream of heated humidified gases at a pressure above atmospheric to auser 2. The system 1 includes a gases supply unit or blower unit 3 whichin use receives gases from atmosphere and passes these through a fanunit 17 or similar inside the blower unit so that when the gases leavethe blower unit 3, they are at a pressure above atmospheric, and areflowing at a certain flow rate. A humidifier unit 4 is locateddownstream from the blower unit 3, and in use receives the flow ofpressurised gases from the blower unit 3. The humidifier unit 4 includesa water chamber 5 which in use contains a volume of water 7. The volumeof water 7 in the chamber 5 is in use heated—in the embodiment shown inFIG. 1, the water 7 is heated by a heater plate 6 located underneath thechamber 5. The gases from the blower unit 3 pass into the chamber 5 viaan entry port 8, the gases passing through the chamber 5 and across thesurface of the water 7, becoming heated and humidified as they do so.The gases then pass out of the humidifier chamber 5 via a humidifieroutlet port 9.

It should be noted that a modular humidification system has beendescribed above—that is, a system where the humidifier unit 4 is aseparate unit to the blower unit 3. An integrated humidification systemcould also be used—that is, a system where the blower unit and thehumidifier unit are two integral parts of a single unit, or where theblower unit and the humidifier unit are rigidly attached or connectedtogether in use.

Furthermore, it is preferable, although not necessary, that the overallrespiratory system have a modular configuration. In the preferredembodiment the individual components are releasably interconnected toform the complete respiratory system. The modularity of the preferredsystem allows individual components to be maintained and replaced asnecessary. It also permits components to be interchanged to meetindividual user requirements. This is particularly useful ininstitutional applications, where a base unit (such as the blower andhumidifier unit) can be used for different recipients at different timeswhile the patient interface is interchanged to suit the particular user.

In use, a main supply conduit 19 is connected to the humidifier outlet9. The heated and humidified gases stream exits the humidifier unit 4via the humidifier outlet 9 and enters the main supply conduit 19,passing along the supply conduit 19 to an interface assembly 10 which isconnected to the user end of the supply conduit 19. The supply conduit19 can either be directly connected to the interface assembly 10, asshown in FIG. 1, or an intervening interface conduit 190 can be used toconnect between the main supply conduit 19 and the interface assembly10, as shown in the embodiments of FIGS. 2, 3 and 4. Where the supplyconduit 19 is referred to below, this should be taken to mean either thesupply conduit 19 by itself, or in combination with the interfaceconduit 190.

2. Supply Conduit and Interface Conduit

In the preferred embodiment, the supply conduit 19 is a flexible tubeformed from a plastic type material, many different variations of whichare known in the art. One end of the supply conduit 19 is connected tothe humidifier outlet port 9, with the other end connected eitherdirectly to the interface assembly 10, or connected to the distal end190 a of the interface conduit 190, the interface conduit 190 connectedto the interface core section 11. The most preferred form of interfaceconduit 190 is approximately 30 cm or 1 foot in length, with an externaldiameter of between 1-2 cm and a thin ribbed wall, the ribs beingapproximately 2-3 mm thick and the wall between the ribs beingsignificantly less that 1 mm thick. However, it should be noted thatvariations from these dimensions are possible without departing from thescope of the invention, and for example a non-ribbed conduit could beused if required. It should further be noted that ‘flexible tube’ as itis used in this specification should be taken to mean that the tube orconduit is flexible enough so that it is capable of being bent ordeformed repeatedly (for example, by bringing the two ends of theconduit together, or by tying a loose knot in the conduit if it is longenough, say, approximately 30 cm or more in length), with the tube orconduit returning to its original undeformed shape with little to noplastic deformation occurring, every single time the tube or conduit isbent or deformed in this manner.

In the most preferred form, neither of the supply conduit 19 or theinterface conduit 190 will rigidly support their own weight when held atone end so that the main body of the conduit extends outwards generallyhorizontally from the held end. Over a 20-30 cm length of supply conduit(which has a diameter of 1-2 cm and a wall thickness at the ribs of 1-3mm and a wall thickness between the ribs of less than 1 mm), theunsupported end of the interface conduit will bend to face substantiallydirectly downwards. For example, the interface conduit of the Swift LT™interface is formed in such a manner that over a 20-30 cm length, theunsupported end will bend downwards so that it points substantiallyvertically downwards. The interface conduit used in the Opus is somewhatstiffer, but will still bend through an angle of around 45 degrees. Bothof these conduits are flexible for the purposes of this specification,and should not be thought of as ‘rigid’ or ‘semi-rigid’ (see Lexiconsection for more details). The main supply conduit 19 is of similarflexibility to both of these items.

The conduits 19, 190 connect to each other, or to the interface assembly10, or both, by a friction push fit, a bayonet connection or similar, orby any other suitable connection as might be known in the art.

3. Nasal Pillow Variations

3.1 Interface Assembly

Specific preferred forms of an interface assembly 10 are shown in FIGS.2, 3, and 4 as interface assembly 200, interface assembly 300 orinterface assembly 400. The interface assemblies 200, 300, 400 have anumber of common elements and differences as will be described below. Inthe description below, the element numbering conforms to the followingconvention: For the embodiment of FIG. 2, the elements unique to thatembodiment will be numbered e.g. 201, 210, etc. The equivalent uniqueelements on the embodiments shown in FIGS. 3 and 4 will be numbered e.g.301, 310 and 401, 410 respectively. If the element is being referred toin a general sense, it will be referred to as e.g. 1, 10 etc to showthat the description is applicable to all the embodiments shown in FIGS.2, 3, 4, and could also be applied as a general description to other,general, embodiments not specifically shown.

The interface assembly 10 (e.g. assemblies 200, 300, 400) are assembledfrom two main parts: an interface core portion or interface core section11, and a headgear assembly 12.

The interface core section 11 and the supply conduit 19 (eitherincluding or excluding the interface conduit 190) are mutually adaptedso that one end (the patient end or proximal end) of the supply conduit19 is fluidically or gaseously connected to the interface core section11 in use, the interface core section 11 adapted so that the supply ofheated, humidified gases is provided to the interior of the interfacecore portion 11 from the supply conduit 19 via this connection. Thepreferred forms of this connection will be described in detail below.

3.2 Headgear Assembly

The headgear assembly 12 is formed from two main items: a set of arms 13that extend in use one from each side of the interface core portion 11,and a set of headgear straps 14. In the preferred embodiments, the arms13 are formed from either a flexible or a semi-rigid plastic, backedwith neoprene, foam, or similar to form a cushion portion, the cushionportion resting against the face of a user in use.

The arms 13 can be connected to the interface core portion 11 in anumber of ways. For example, arms 213 could be integrally formed withthe interface core portion 211, as shown in the embodiment of FIG. 2.

Alternatively, arms 313 could be connected to the interface core portion311 as shown in the embodiment of FIG. 3a , the connection made in sucha manner as to allow the arms 313 to be rotatably adjusted with respectto the interface core portion 311. The embodiment of FIG. 3a with theadjustable arms shows an interface assembly 300 that has an interfacecore portion 311 and arms 313. The interface ends of the arms 313 arerotatably connected to the interface core portion 311 by way of a‘rotating barrel’ connection as on the ResMed Swift™ LT, which allowsthe arms 313 to rotate relative to the interface core portion 311, andstill remain connected. The mutual connection is formed so that when theconnection is made, the arm 313 will remain in the position to which auser rotates it once it is rotated to that position—it will not freelyrotate unless manipulated by a user.

For all of the preferred forms, the headgear straps 14 extend around therear, or over the top of a user's head (or both) in use, to support theinterface assembly 10 in position in use. In the embodiment of FIG. 2,the ends of the arms 213 in use co-locate with the ends of the headgearstraps 214, with the ends of the arms 213 and the ends of the headgearstraps 214 mutually adapted to connect together in use to hold theinterface assembly 200 in position. In this form, the ends of the mainstrap 214 include two patches of Velcro™ on the outer surface at eachend—one ‘hook’ patch and one ‘loop’ patch. When each of the ends isdoubled back on itself to form a loop, the Velcro™ patches engage tohold this loop together. In use, the ends 224, 225 are passed one eachthrough slots on the ends of the arms 213 and then doubled back onthemselves to engage the headgear assembly 212 with the core section211. This arrangement could be used on other embodiments if required.

In alternative embodiments, such as those shown in FIGS. 3 and 4, theheadgear straps 314, 414 could be formed as an extension of the cushionportion, with the headgear straps 314, 414 formed from neoprene orsimilar.

It is preferred that all the different embodiments of headgear straps 13include a secondary upper strap 20 which passes across the top of auser's head, as well as the main strap 14 which passes behind the user'shead. The secondary upper strap 20 is arranged so that it passes acrossthe top of a users head, with each end of the secondary strap 20connecting to the main strap 14 just behind the ears of a user. Each ofthese straps 14, 20 includes an adjustment mechanism such as buckles 15a, 15 b or similar. These could be Velcro™ adjusters or buckles aspreferred. The headgear secondary upper strap 20 could also beindependently formed and connected to the main strap 14. The adjustmentscould be at any location on the strap that is convenient—sides, front orrear. The straps 14, 20 could be of different widths or thicknesses asrequired for user comfort. For example, in the most preferred form, themain strap 14 is wider than the secondary strap 20.

Suitable strap materials may include a woven elastic strip or a narrowstrip of foam and fabric, such as Breathoprene™. Alternatively, theheadgear could be formed from silicone, or coated with silicone. Theheadgear arms could be padded or cushioned on their inside surfaces ifthey are formed from silicone, in order to increase user comfort.Padding could also be added to the preferred form of arms—those madefrom Breathoprene™ or similar.

3.3 Interface Core Section—General

The interface core section 11 of the preferred forms functions as asupply manifold inlet, receiving breathing gases from the breathing gasconduit 19.

Preferably the interface core section incorporates a connector junctionadapted to engage with a reciprocal connector junction on anotherbreathing system component. Such components may include an elbowconnector, the interface conduit or the supply conduit 19.

Preferably the respective connector junctions incorporate a reciprocalsnap or push fit inter-engagement. However alternate connectionmechanisms are also known and are equally as applicable.

When the connector junctions are appropriately engaged, an interfaceconnection is formed between the respective breathing system components.The resulting interface connection locates and seals the respectivebreathing system components relative to each other.

Preferably the interface connection is capable of adapting to changes inthe users position. Generally the interface connection compensates foruser movements by permitting the respective components on either side ofthe interface connection to move in defined paths relative to eachother. One example is the swivel connection pictured in FIG. 3.

The interface core section 11 can be formed as a single component whichreceives the supply conduit 19 directly, or as separate components thatare inter-connected after fabrication.

The integrated embodiment of the interface core section 11 incorporatesa connector junction which is adapted to receive the patient end of thesupply conduit 19. In this form, the end of the supply conduit 19 isconnected directly to the one-piece interface core section 11, forexample, by direct interconnection with the interface core section 11connection junction.

In the alternative, modular embodiment, the supply conduit 19 connectsto a sub-component or sub-assembly (such as an elbow connector) which isin turn connected to the interface connection junction. Thesub-component is preferably incorporated as part of the interface coreportion 11 when the interface core section 11 is assembled; but isgenerally fabricated as a separate item.

3.4 Interface Core Section—First Preferred Form

An example of a modular interface core section 211 is pictured in FIG.2. The interface core section 211 includes a manifold inlet section211-1 and an elbow connector 211-2.

One end of the elbow connector 211-2 is fabricated into a hollow ballsegment. The manifold section 211-1 includes a complimentary socketadapted to receive the ball segment. In the assembled core section 211the ball segment and socket combine to form a ball and socket connectionor a ball joint.

The ball joint connection permits the manifold inlet 211-1three-dimensions of movement (movement in three planes) relative to theelbow connector 211-2.

The connection allows unrestrained relative rotation (swivel) of themanifold inlet 211-1 and the elbow connector 211-2 about the axis of thesocket. In the embodiment particularly shown in FIG. 2c , the socketaxis on the manifold inlet 211-1 is aligned with the exterior apertureon the elbow connector 211-2 from which the ball segment protrudes.

The ball joint connector of the preferred form shown in FIG. 2 alsopermits restricted motion of the components transverse to the socketaxis. This motion equates to up/down and side/side rotation of the elbowconnector 211-2 when viewed by a user wearing the interface in theintended orientation.

3.5 Interface Core Section—Second Preferred Form

An example of a second preferred form of interface core section 311 thatincludes an elbow connector is shown in FIG. 3a . A manifold portion ormanifold section 311-1 is shown, the manifold section 311-1 including anaperture located at the front of the manifold section 311-1. An elbowconnector 311-2 is connected to the manifold section 311-1 via theaperture, with one end of the elbow connector 311-2 locating into orconnected to the aperture. The manifold section 311-1 and the elbowconnector 311-2 are mutually adapted to provide a 360 degree swivel—theelbow connector 311-2 and the manifold section 311-1 can swivel orrotate relative to one another in use, as shown in FIG. 3b . Themanifold section 311-1 and the elbow connector 311-2 are assembledtogether to form part of the interface core section portion 311 of theembodiment of FIG. 3.

3.6 Interface Core Section—Third Preferred Form

Yet another example of an interface core section that includes an elbowconnector is shown in FIG. 4. The manifold section 411-1 includes anaperture at one side of the manifold section 411-1. This aperturereceives one end of an elbow connector 411-2 in use, the elbow connector411-2 adapted to rotate freely relative to the manifold section 411-1,the plane of rotation of the elbow connector aligned back-front of auser 2 in use, rather than side-side as in the embodiment of FIG. 3 orFIG. 2.

3.7 Interface Core Section—Pillow Section

The interface core section 11 further includes a nasal pillow section 50(e.g. nasal pillow section 250 as shown in FIG. 2d ).

The nasal pillow section 50 incorporates nasal pillow portions whichinclude caps 50-1 that are adapted to substantially seal against thenares of a user, the heated, humidified gases stream entering the pillowsection 50 and passing through the pillow caps 50-1 into the nasalcavity of a user. ‘Substantially seals’ as it is used in thisspecification should be taken to mean that perfectly sealing against thenares with no leaks is the most desirable outcome. However, a smalldegree of leakage in use is almost certainly inevitable, and a personskilled in the art will understand that the phrase ‘substantiallysealing’ is intended to indicate that a very small amount of leakage maysometimes, but not always, occur. As the pillow caps 50-1 aresubstantially sealed against the nares of a user, all or substantiallyall of the stream of gases which passes through the manifold section 11and the nasal pillow section 50 will be delivered to a user.

As shown in the preferred embodiments of FIGS. 2, 3 and 4, the pillowsection 50 is composed of two main sub-parts that form a continuous orintegrated whole in use: a pillow portion, which is itself formed from apair of stems 50-3 and a pair of associated pillow caps 50-1, the caps50-1 locating into the nares of the user or patient 2 in use, and apillow manifold section or pillow gasket 50-2, which is connected to theinterface core section 11 in use, so that gases passing through the coresection 11 in use then pass into the pillow gasket 50-2 and then intothe pillows.

In order to aid in sealing the nasal pillow caps 50-1 against the naresof a wide variety of users, each of whom will have differently shapedand sized nostrils, the pillow caps 50-1 and stems 50-3 are in thepreferred form formed from a soft and supple material with a high degreeof flexibility, such as silicone or similar. Preferred forms of thenasal pillow section 50 are described in detail below.

The nasal pillow section 50 can either be formed separately from therest of the core portion 11, or integrally formed with the core portion11. In the preferred embodiments as shown in FIGS. 2, 3 and 4, the nasalpillow section 50 is separate from the core portion 11. The nasal pillowsection is formed from two main parts: a base portion or nasal pillowgasket portion 50-2 and a nasal pillow portion composed of stems 50-3and caps 50-1. The attachment or connection of the nasal pillow portionto the remainder of the core portion 11 is achieved by attaching thegasket portion 50-2 to the manifold portion 11-1, with the pillowportion preferably (although not always) integrally formed with thegasket portion 50-2. The embodiments of FIGS. 2, 3 and 4 show thisintegral form of connection.

In the preferred embodiments, at least the pillow caps and stalks 50-1,50-3 are formed from a supple and flexible material, such as siliconerubber.

3.8 Pillow Gasket—First Preferred Form

The first preferred form of pillow gasket portion 250-2 shown in FIG. 2shall now be described with particular reference to FIG. 2 d.

The pillow gasket portion 250-2 includes an open lower face or openlower portion 237 which corresponds in use to the open rear face (notshown) of the manifold section 211-1. In use, the perimeter of the openlower portion 237 of the pillow gasket portion 250-2 is connected to theopen rear face of the manifold section 211-1. The wall 237 a whichsurrounds the open lower portion 237 slots or locates into the open rearface of the manifold section 211-1. It can be seen that all of the gasespassing through the manifold section 211-1 will pass into the pillowgasket portion 250-2 and from there into the caps 250-1 of the nasalpillows. It should be noted that the pillow gasket portion 250-2 can beattached and removed repeatedly from the manifold portion 211-1 asrequired by a user. Optionally, if required, a key 238 can be formedinto the wall section 237, the key 238 slotting into a correspondingslot in the manifold section 211-1 to ensure the pillows are correctlyoriented in use.

In the first preferred form of pillow gasket portion 250-2, the pillowgasket 250-2 is shaped so that the two side portions are slightly angledtowards one another. That is, the top surface which covers the open rearface of the manifold 8 appears to have a V-shape when viewed from thefront, with the stems 250-3 of the pillows mounted one on each of thetwo sub-surfaces or inner faces of the ‘V’. The angle of the ‘V’ is notacute—each edge or plane of the ‘V’ of the pillow gasket portion 250-2is raised by a few degrees only (e.g. 5-10 degrees). The stems 250-3 ofthe pillows are mounted one on each of the two planes, and are in thismanner angled inwards towards one another slightly in the most preferredform (although there are of course many other ways in which this couldbe achieved without creating a ‘V’-shape).

In the preferred form, as described above, the nasal pillows and thegasket portion 250-2 are formed as a one-piece item. However, the pillowportions could be removably connected to the gasket portion 250-2,either individually or as a pair. For example, the gasket portion 250-2could include a pair of stub bases to which the pillows are press-fittedin use, the stub base and the base of the stem 250-3 being mutuallyadapted to connect together by way of a press-fit, a keyed connection,or similar. This would potentially allow pillows which are of differentshapes or sizes to be fitted to the pillow gasket portion 250-2. Thiswould be advantageous if a user required pillows moulded specifically tothe shape of their nares, or pillows of different sizes. This would alsoallow a range of standard pillows to be manufactured, the range havingdifferent sizes or different shapes, or both. This would provide a rangeof off-the-shelf adjustment.

The rear of the pillow gasket portion 250-2 can include a lip cushion239, which is a rounded elongate surface on the rear of the pillowgasket portion 250-2, the lip cushion 239 resting on the upper lip of auser in use. In the most preferred form the lip cushion 239 is hollowand formed from the same supple and flexible material as is used to formthe gasket and pillows. The lip cushion 239 rests against the top lip ofa user in use. The lip cushion could, in alternative forms, be formedfrom foam or similar.

Alternatively, the pillow gasket portion 250-2 can be formed so that itdoes not contact the upper lip of a user 2. Instead of being roundedoutwards or bulging outwards convexly to contact the users lip as a lipcushion as described above, the inner surface of the pillow gasketportion 250-2 is either straight or concave, so that contact with theusers face occurs only at the caps 250-1 of the nasal pillows and thereis no contact between the face of a user 2 and the pillow gasket portion250-2—contact only takes place at the caps 250-1 of the nasal pillows.

3.9 Pillow Gasket—Second Preferred Form

The second preferred form of pillow gasket is shown in FIG. 3, and isdescribed below with particular reference to FIG. 3c . This secondpreferred form shares many of the features of the first preferred form.The main difference is that the pillow gasket portion 350-2 is held inposition on the manifold section 311-1 by a pair of protrusions 338 onthe gasket portion 350-2 which slot into corresponding apertures on themanifold section 311-1. In the form shown in FIG. 3a , the protrusions338 and the apertures are aligned centrally on the top and bottomsurfaces of the manifold section 311-1 and the gasket portion 350-2.However, this potentially allows the gasket portion 350-2 to be fittedupside-down on the manifold section 311-1, so these can be offset to thesides if required, so that the gasket portion 350-2 can only beconnected in one (correct) orientation.

3.10 Pillow Gasket—Third Preferred Form

A third preferred form of pillow gasket is shown in FIG. 4, and isdescribed below with particular reference to FIG. 4b . As with theprevious forms, the third preferred form has a manifold section and agasket section—manifold section 411-1 and gasket section 450-2 in thisthird preferred form. The manifold section 411-1 is formed from asemi-rigid plastic, with a central cross-brace body section 411-1 a, andtwo end sections 411-1 b and 411-1 c. A cap 470 closes off the otherend—end 411-1 c—in use.

The manifold section 411-1 and the main body of the gasket section 450-2of the pillow section 450 of this third preferred form in use have theoverall general form of a cylinder, which in use is aligned across thetop lip of a user. The manifold section 411-1 includes an aperture 411-1b at one side of the manifold section 411-1, adapted to receive theelbow connector 411-2 in use. The elbow connector 411-2 and the manifoldsection 411-1 are adapted to rotate freely relative to each other inuse, the plane of rotation of the elbow connector aligned back-front ofa user 2 in use, rather than side-side as in the embodiment of FIG. 3 orFIG. 2.

In this third preferred form, the pillow section 450 is removablyattached to manifold section 411-1. When the pillow section 450 and themanifold section 411-1 are connected, the pair of nasal pillow stems450-3 and caps 450-1 extend outwards and upwards from the cylindricalmain portion.

The gasket section 450-2 of the pillow section 450 has the generaloverall form of a cylinder, the gasket section 450-2 and the manifoldsection 411-1 are mutually sized so that the gasket section 450-2 slotsbetween the end sections 411-1 b and 411-1 c. The gasket section 450-2includes a slit 451 which runs along the length of the cylindrical body,at the bottom front of the cylindrical body, opposite the pillow stems450-3. In use, the slit 451 in the gasket section 450-2 is held closedby engagement of the edges of the slit with the cross-brace body section411-1 a.

The ends of the headgear straps 414 in this third preferred form includeconnectors 452 which engage with the ends of the manifold section 411-1to hold the manifold section and pillow section 450 in place on the faceof a user in use.

Three preferred forms of interface assembly have been given as examplesabove, with reference to FIGS. 2, 3 and 4. It should be noted that theinvention is not limited to use with these example (or variantsthereof), and could be used with any suitable interface. For example,the invention as described herein could also be used with the interfaceassembly described in U.S. application 61/082,877, the contents of whichis herein incorporated by reference.

3.11 Pillow Portion

As described above, there are three particularly preferred forms ofinterface assembly, which have several common elements and severalelements which are unique to that particular preferred form. Severalvariations of pillow design will now be described with particularreference to particular Figures. It should be noted that thesevariations or embodiments of pillow design are suitable for use with anyof the variations of interface assembly as described above, or othervariations of these interfaces.

In the description below, the element numbering follows the followingnumbering convention: For the embodiment of FIG. 5, the elements withinthe figures will be numbered 500, 501 and so on. For the embodiment inFIG. 6, the elements within the figures will be numbered 600, 601, 650-1a and so on. This numbering convention is followed in FIG. 5 onwards.The pillow portion is generally comprised of stalks 50-3 and caps 50-1.The pillow portions described earlier, and indicated by stalks 50-3 andpillow caps 50-1 indicate a ‘general’ pillow portion. The pillow portionmay take two general forms, which are described later. The pillowportions described in FIGS. 5 to 38 c are specific preferred andalternative forms of the two general forms of the pillow portions, andare numbered 500, 600, and so on. As outlined above, the pillow portionsare composed of stems or stalks, and caps. In the preferred andalternative forms of FIGS. 5a to 9c , the stems/stalks are numbered550-3, 650-3, etc, and the caps are numbered 550-1, 650-1, etc.

The various forms and embodiments of the pillow portion described belowor pillow section described above can be used with face masks also. Thepillows, pillow portion or pillow section can be used with any face maskthat delivers gases to the nose of patient or user. In particular thepillows, pillow portion or pillow section are suitable for use with a‘hybrid’ type face mask. A ‘hybrid’ face mask is a face mask thatdelivers gases to the nose and mouth of a patient or user. A typical‘hybrid’ face mask generally includes a portion adapted to deliver gasesto a user or patient's nasal passages. The ‘hybrid’ face mask alsogenerally includes a portion adapted to deliver gases to a user or apatient's mouth or oral passage. The various forms and embodiments ofthe pillows, pillow portion or pillow section as described in thisspecification can be used with a face mask to deliver a portion of gasesto a user or patient's nasal passages.

3.12 Pillow Portion—First General Form

An example of the first general form of the pillow portion is shown inFIG. 5. In the first general form of the pillow portion, the pillowportion comprises two main parts: a stalk 50-3 that connects the pillowportion to the gasket (as described earlier) and a cap section 50-1.Gases pass through the gasket portion and into the pillow portion at thebase of the stalks 50-3, exiting at the top of the stalk 50-3. Thesecond part of the pillow portion comprises a cap 50-1, the base ofwhich is connected to the top of the stalk 50-3 and the top of which isinserted into a patient or user's nostril or nare, the outer surface ofthe cap sealing around the perimeter of the user's nostril or nare. Thecap 50-1 is generally much wider at its base than at the top end of thecap 50-1.

In this first general form the cap comprises an outer cap 50-1 a and aninner cap 50-1 b, with the outer cap 50-1 a sealing against the nare ornostril of the user. The lower ends of the caps 50-1 a and 50-1 b aregenerally co-located or congruent where they are located on the top ofthe stalk 50-3. The caps 50-1 a and 50-1 b are generally concentricallynested—meaning the inner cap 50-1 b is nested inside the outer cap 50-1a, with the outer cap 50-1 a surrounding or enveloping the inner cap50-1 b. Generally the upper rims of the inner 50-1 b and outer 50-1 acap are aligned vertically, meaning generally the outer cap 50-1 a andthe inner cap 50-1 b are at the same height. The gasket includes 2stalks and caps extending from it. The two caps are angled inwardstowards each other on the gasket portion, as can be seen in FIGS. 5a,6a, 7a, 8a, 9a, 10a, 11a and so on. Since the caps are angled towardeach other the outer cap 50-1 a usually extends further upward than theinner cap 50-1 b, when in use.

The inner cap 50-1 b and outer cap 50-1 a are generally arrangedconcentrically with a common central axis, as can be seen in therespective figures (for example FIG. 10c, 12c , 20 and so on). The cap50-1 is wider at its base than the stalk 50-3. The outer cap 50-1 a andinner cap 50-1 b merge at their bases, with the base extending fromoutwards almost perpendicular to the axis of the stalk 50-3 beforeangling upwards and inwards. The shape of the inner and outer capsallows the caps to form a substantial seal with the nostril of the user,when in use. The walls of the inner 50-1 b and outer 50-1 a caps arecurved upwards and outwards to help the cap conform to a user's nostriland to assist in guiding a stream of gases from the pillow portions tothe nostrils of a user. Preferably the walls of the inner 50-1 b andouter 50-1 a caps are curved along a parabolic arc.

The numbering of the stalks and caps changes from figure to figure andembodiment to embodiment while maintaining the common numbering elementsidentified above. For example the stalk in FIG. 12 is 1250-3 and in FIG.13 is 1350-3 and so on. The inner cap in FIG. 12 is 1250-1 b and in FIG.13 is 1350-1 b and so on. The outer cap in FIG. 12 is 1250-1 a and inFIG. 13 is 1350-1 a and so on.

3.13 Pillow Portion—Second General Form

An example of the second general form of the pillow portion is shown inFIG. 25. In the second general form of the pillow portion, the pillowportion comprises two main parts: a stalk 50-3 that connects the pillowportion to the gasket (as described earlier) and a cap section 50-1.Gases pass through the gasket portion and into the pillow portion at thebase of the stalks 50-3, exiting at the top of the stalk 50-3. Thesecond part of the pillow portion comprises a cap 50-1, the base ofwhich is connected to the top of the stalk 50-3 and the top of which isinserted into a patient or user's nostril or nare, the outer surface ofthe cap sealing around the perimeter of the user's nostril or nare. Thecap 50-1 is generally much wider at its base than at the top end of thecap 50-1.

The second general form of the pillow portion, the cap comprises anouter cap 50-1 a and an internal air delivery tube 60, with the outersurface of the outer cap 50-1 a sealing against the nostrils of a user.The lower end of the outer cap 50-1 a is joined to the tube 60. Theouter cap 50-1 a and tube 60 are generally concentrically nested—meaningthe tube 60 is nested inside the outer cap 50-1 a, with the outer cap50-1 a surrounding or enveloping the tube 60.

Preferably the air delivery tube 60 is substantially rigid and stifferthan the outer cap 50-1 a. This means the air delivery tube 60 does notflex or bend as much as the more flexible outer cap 50-1 a does.Preferably the outer cap 50-1 a is flexible and supple enough to undergoelastic deformation while in use and return to its original positionwhen not in use.

The cap 50-1 is wider at its base than the stalk 50-3. The outer cap50-1 a and air delivery tube 60 merge at their bases, with the baseextending from outwards almost perpendicular to the axis of the stalk50-3 before angling upwards and inwards. The shape of the air deliverytube 60 outer cap allows the caps to form a substantial seal with thenostril of the user, when in use. The walls of the outer 50-1 a cap arecurved upwards and outwards to help the cap conform to a user's nostriland to assist in guiding a stream of gases from the pillow portions tothe nostrils of a user. Preferably the walls of outer 50-1 a cap flareoutwards and upwards such that the flare may allow the outer cap 50-1 ato form a substantial seal with the nostril of the user, when in use.

The numbering of the stalks, caps and air tube changes from figure tofigure while maintaining the common cumbering element identified here.For example the stalk in FIG. 25 is 2550-3 and the stalk in FIG. 26 is2650-3 and so on. The cap in FIG. 25 is 2550-1 and in FIG. 26 is 2650-1and so on. The air delivery tube in FIG. 25 is 2560 and in FIG. 27 is2760 and so on.

3.14 Pillow Portion—Third General Form

An example of a third general form of the pillow portion is shown inFIG. 39. In the third general form the pillow portion comprises twoparts: a stalk 50-3 (3950-3 in the specific embodiment shown in FIG. 39)which connects the pillow portion to the pillow gasket 50-2 (250-2 inthe specific embodiment shown in FIG. 39) and a cap 50-1 (3950-1 in thespecific embodiment shown in FIG. 39) that extends from the top of thestalk 50-3. Gases pass through the pillow gasket and into the pillowportion at the lower end of or base of the stalk 50-3. Preferably thestalks curve upward and outward. The numbering of the stalks changesfrom embodiment to embodiment and figure to figure, but follows thegeneral convention outlined above. That is, for example, the stalk inFIG. 39 is numbered 3950-3, in FIG. 40 the stalk is 4050-3 and so on.The gasket numbering has been described earlier.

The second part of the pillow portion is the cap 50-1, the base of cap50-1 being connected to the top of the stalk 50-3. The top of the cap isinserted into a user or patient's nares or nostrils, with the outersurface of the cap 50-1 sealing against a user's nostrils or nares. Thegasket portion includes a pair of caps extending from it. The cap 50-1is generally wider at its base than at its top end, where the gasesexit. The rims of the two caps are generally aligned. The caps areangled inward toward each other on the gasket portion.

The cap 50-1 is wider at its base than the stalk 50-3. The shape of thecap 50-1 allows the cap to form a substantial seal with the nostril ofthe user, when in use. The cap 50-1 preferably curves upwards andoutwards to help conform to a user or patient's nostril and assist inguiding a stream of gases from the pillow portion into the nostrils of auser. The walls of the cap 50-1 preferably curve along an arc. The cap50-1 preferably flares upwards and outward from the base such that inuse the flare of the cap 50-1 allows the cap 50-1 to form a substantialseal with the nostril of the user. The numbering of the cap is alteredfrom embodiment to embodiment and figure to figure while maintaining acommon element—50-1. For example, the cap shown in FIG. 40 is numbered4050-1, the cap in FIG. 39 is numbered 3950-1 and so on.

3.15 Specific Pillow Portion Embodiments

An embodiment of nasal pillow portion is shown in FIGS. 5a, 5b and 5c .In this variation, the pillow portion is shown as being used with thepillow gasket portion 350-2 (although as outlined above, these could beused with pillow gasket portion 250-2 or pillow gasket portion 450-2).In this embodiment, the pillow section is formed from the pillowportions and the pillow gasket portion.

As seen in FIGS. 5a-5c , the embodiment of the nasal pillow portion ismade up of the first general form of the pillow portion (describedabove). The specific

In the preferred form of this embodiment, the walls of the inner cap550-1 b and the outer cap 550-1 a taper in cross sectional thickness asbest seen in FIG. 5c . The walls of the inner cap 550-1 b and the outer550-1 a are thicker at the lower end. The wall of the outer cap 550-1 ais thicker at the base 504 of the outer cap 550-1 a than at the rim 506of the outer cap 550-1 a, and the wall of the inner cap 550-1 b isthicker at the base 505 of the inner cap 550-1 b than at the rim 507 ofthe inner cap 550-1 b. Alternatively the thickness of the walls of theinner and outer cap may be constant or the wall thickness of one of thewalls may taper while the wall thickness of the other wall may remainconstant.

The inside surface of the wall of the outer cap 550-1 b contains atleast one and preferably a pair of ribs 501. In alternate embodiments,the inner or inside surface of the wall of the outer cap 550-1 a maycontain three or more ribs 501. If a series of ribs is used, the ribs501 can be positioned at regular or differing intervals around theperimeter of the inside surface of the wall of the outer cap 550-1 a.The pair of ribs 501 extend only a partial length along the height ofthe inside wall of the outer cap. Preferably the height of the rib isless than the height of the outer cap 550-1 a. The ribs can have thesame height as one another, or different heights. The ribs can also havedifferent thicknesses, or the same thickness.

The rib could also be positioned at any location along the inside wallof the outer cap 550-1 a—for example, with the lower end of the rib atthe base 504 of the outer cap 550-1 a or at the base 505 of the innercap 550-1 b, near the air gap. A further alternative is that the upperend of the rib is at the rim 506 of the outer cap 550-1 a. However,preferably the rib does not extend all the way to the top or the bottomof the outer cap 550-1 a. As shown in FIG. 5c , in this embodiment, eachof the pair of ribs 501 is around two-thirds to three-quarters of theway up the inner surface of the wall of the outer cap 550-1 a. However,each one of the pair could be in different positions in alternativeembodiments.

It should particularly be noted that the ribs 501 of this embodiment arerounded so that their ends blend into the inner surface of the outer cap550-1 a—that is, they do not have ‘cornered’ or ‘sharp’ upper and loweredges or surfaces. The rib 501 is thicker in the middle than it is atits extremes, and generally the majority of the profile shape follows anarc or curve from end to end. The width of the ribs 501 is preferablyconstant, (‘Thicker’ in this context means that the central portion ofthe rib extends further inwards towards the inner cap 550-1 b than theends. ‘Width’ in this context is the side-side dimension of the rib501—that is, the dimension into and out of the page in FIG. 5c . In thisembodiment, the width of the pair of ribs is constant).

It should be particularly noted that the ribs 501 do not run the entirelength of the wall 550-1 a: the rib or ribs 501 only run aroundone-third to one-half of the total length or height of the wall 550-1 a.

It should also be noted that in the preferred form shown in FIG. 5, therib or ribs 501 are located towards the top of the wall 550-1 a, and nottowards the base.

Surprisingly, it has been found that a rib or ribs 501 in this form actto increase the strength of the outer pillow wall 550-1 a in certainareas to control and manipulate the collapse of the outer pillow wall550-1 a when this is inserted into the nostril of a user. By controllingthe collapse, the pillow wall 550-1 a will have more movement in someareas rather than others. This is advantageous as pillows can beproduced which are both more comfortable and which also offer goodsealing properties against the nares of a user.

The addition of a pair of ribs 501 spaced equidistant around theperimeter of the inner surface of the outer cap 550-1 a helps to improvethe strength of the rim 506 of the outer cap 550-1 a in order tominimise the collapse of the rim 506 into the air path. However, it hassurprisingly been found that having a rib 501 that does not extend allthe way to the top of the wall or all the way to the base of the wall550-1 a still provides strength, helps to maintain structure of the caps550-1 a and 550-1 b in use and at the same time helps to ensure that therim 506 of the outer cap 550-1 a is still flexible to a degree, andcomfortable for a user when inserted into the nostril of a user

The addition of the rib 501 also helps to improve the feel of positiveaffirmation of the pillow 500 being correctly inserted into the nostril,from the user's point of view, to reduce the occurrence of the pillow500 being incorrectly fitted.

A further embodiment of the pillow portion is shown in FIGS. 6a, 6b and6c . In this variation, the pillow portion is shown as being used withthe pillow gasket portion 350-2 (although as outlined above, these couldbe used with pillow gasket portion 250-2 or pillow gasket portion450-2). In this embodiment the pillow section is formed from the pillowportions and the pillow gasket portion.

As seen in FIGS. 6a-6c the embodiment of the nasal pillow portion ismade up of the first general form of the pillow portion. There arespecific variations that will be described below.

In the preferred form of this embodiment the wall of the inner cap 650-1b and the outer cap 650-1 a taper in cross sectional thickness, as bestseen in FIG. 6c . The walls of the inner cap 650-1 b and the outer cap650-1 a are thicker at the lower end. This means the thickness of thewall of the outer cap 650-1 a is thicker at the base 604 of the outercap 650-1 a than at the outer rim 606 of the outer cap 650-1 a, and thatthe thickness of the wall of the inner cap 650-1 b is thicker at thebase 605 of the inner cap 650-1 b than at the rim 607 of the inner cap650-1 b. Alternatively the thickness of the walls of the inner and outercap may be uniform or the thickness of one of the walls may taper whilethe other wall has uniform wall thickness. The walls of the inner andouter caps are curved to help them conform to the nostrils of a user.This helps to provide an effective seal with the user's nostril and toguide a stream of gases from the pillow portions into a users nostrils.

The outer surface of the wall of the inner cap 650-1 b includes a riband preferably a pair of ribs 601. In alternate embodiments, the outersurface of the wall of the inner cap 650-1 b may contain three or moreribs 601. If a series of ribs are used, the ribs 601 may be positionedat regular or differing intervals around the perimeter of the outersurface of the wall of the inner cap 650-1 b. All the ribs may be ofidentical length. Alternatively the rib or ribs may have varyinglengths. The length may also vary from rib to rib. The pair of ribs 601extend only a partial length along the height of the outer wall of theinner cap 650-1 b.

The rib or ribs 601 could be positioned at any location along theoutside wall of the inner cap 650-1 b—for example, with the lower end ofthe rib at the base 605 of the inner cap 650-1 b or at the base 604 ofthe outer cap 650-1 a, near the air gap 610. A further alternative isthat the upper end of the rib is at the rim 607 of the inner cap 650-1b. The rib or ribs 601 preferably extends between the rim and the baseof the inner cap 650-1 b. As shown in FIG. 6c , in this embodiment, eachof the pair of ribs 601 are located substantially in the middle of theouter wall of the inner cap 650-1 b and do not join to the rim 607 orthe base 605 of the inner cap 650-1 b, as illustrated in FIG. 6c . Therib may extend between one fifth and four fifths of the height of theinner cap 650-1 b. Preferably the rib extends approximately threequarters of the height of the inner cap 650-1 b. However, each one ofthe pair could be in different positions in alternative embodiments.

It should be particularly noted the ribs 601 of this embodiment arerounded so that the ends of the ribs blend into the outer surface of theinner cap 650-1 b—that is, they do not have ‘cornered’ or sharp upperand lower edges or surfaces. The rib is thicker in the middle than atits extremes. The width of the rib 601 is preferably constant,(‘thicker’ in this context means that the central portion of the ribextends further towards the outer cap 600 a that the ends. ‘Width’ inthis context is the side-side dimension of the rib 601—that is, thedimension into and out of the page in FIG. 6c .)

Surprisingly it has been found that positioning the rib or ribs 601along the outer wall of the inner cap 650-1 b provides an upper pivotfor the outer cap 650-1 a. The rib or ribs 601 act as pivot or a supportand reduces the inwards collapse of the top rim 606 of the outer cap650-1 a as the pillow portion 600 is inserted into a user's nostril.Preventing the total collapse of the top rim 606 of the outer cap 650-1a helps in preventing the outer cap 650-1 a from completely or partiallysealing the orifice of the inner cap 650-1 b. The sealing of the exitorifice of the inner cap 650-1 b can prevent the optimal delivery oftherapy gases. The addition of the rib or ribs 601 could prevent the rim606 of the outer cap 650-1 a from collapsing and sealing the exitorifice.

A common problem with pillow portion comprising two caps is the outercap can collapse and bear on to the inner cap to distort the shape ofthe inner cap, resulting in reduced gases being delivered and anuncomfortable fit for the user. The rib or ribs 601 prevent the outercap 650-1 a from collapsing and bearing on the inner cap 650-1 b, andhence prevent the inner cap 650-1 b from distorting in shape, resultingin a more comfortable fit, a better seal formed with the user's nostrilsand correct amount of gases being delivered to the user.

The addition of the rib or ribs 601 can allow the outer cap 650-1 a toretain its initial flexibility until enough load is applied to forcecontact of the outer cap 650-1 a onto the rib or ribs 601 of the innercap 650-1 b. This characteristic improves the strength of the inner cap650-1 b while maintaining the flexibility of the outer cap 650-1 a.

The locations of the rib or ribs 601 may be varied along the outer wallof the inner cap 650-1 b in order to accommodate shape variations ofnostrils. The ribs support the outside cap 650-1 a deforming innon-uniform directions as the nasal pillow portion 600 is inserted intoa user's nasal passage. The rib or ribs 601 can support non uniformforces applied to the inner and outer caps when the pillow portions 600are in use. This may improve the fit of the pillow portions 600 fordiffering nostrils of various users'.

The rib or ribs 601 on the inner cap 650-1 b help to prevent or reducethe deformation of the inner cap 650-1 b. This reduces or prevents theinner cap 650-1 b from deforming and closing off the orifice in theinner cap 650-1 b. The prevention of the inner cap 650-1 b deforming mayresult in a more comfortable fit and improved therapy to the user. Therib or ribs 601 on the inner cap 650-1 b also help to reduce or preventthe inner cap 650-1 b from folding into the stalk 650-3. This assists increating and maintaining a seal on the nostril wall of the user.

A further embodiment of the pillow portions is shown in FIGS. 7a, 7b and7c . In this variation, the pillow portions 700 are shown as being usedwith the pillow gasket portion 350-2 (although as outlined above, thesecould be used with pillow gasket portion 250-2 or pillow gasket portion450-2).

As seen in FIGS. 7a-7c this embodiment is made up of the first generalform of the nasal pillow portion (described above). The specificvariations will be described below. In the preferred form of thisembodiment the wall of the inner and outer cap taper in cross sectionalthickness as best seen in FIG. 7c . The walls of the inner cap 750-1 band the outer cap 750-1 a are thicker at the base 705 of the inner cap750-1 b and the base 704 of the outer cap 750-1 a, than at the rim 706of the outer cap 750-1 a and the rim 707 of the inner cap 750-1 b.Alternatively the thickness of the walls may be uniform or the thicknessof one of the walls may taper while the thickness of the other wall mayremain uniform.

The outer surface of the inner cap 750-1 b contains at least one butpreferably a pair of ribs 701. In alternate embodiments the outersurface of the wall of the inner cap 750-1 b may contain 3 or more ribs.The rib or ribs 701 can be positioned at regular or differing intervalsaround the perimeter of the outer surface of the wall of the inner cap750-1 b. Preferably the rib or ribs 701 are formed integral to the outerwall of the inner cap 750-1 b. The ribs can be of the same width as eachother (the width being the dimension horizontally across or through therib at any location on the rib) or varying width to one another. Itshould also be noted that the width could vary along the height of therib—for example, one or both of the ribs could be flared (horizontally)towards their bases, and conversely be tapered (horizontally) towardsthe top of the rib. It should also be noted that these variabledimensions could vary from one rib to another. It should still furtherbe noted that the ribs as shown in FIGS. 7a-c are shown having anincreasing thickness from the top (where the ribs blend with the innercap 750-1 b) to the base. This thickness could in alternative forms bemore uniform along the height or length of the rib.

The location of the rib or ribs could also be positioned at any locationalong the outer surface of the wall of the inner cap 750-1 b. Thedistance between each rib 701 could vary or remain in the same along theperimeter of the outer surface of the wall of the inner cap 750-1 b. Therib 701 extends from the top rim 707 of the inner cap 750-1 b to thebase 704 of the outer cap 750-1 a as shown in FIG. 7c . It should benoted the rib is preferably sloped toward the base 704 of the outer cap750-1 a from the top rim 707 of the inner cap 750-1 b. The angle of theslope can be any acute angle relative to the inner cap 750-1 b.Preferably the rib 701 follows the curvature of the outer surface of thewall of the inner cap 750-1 b and the rib may follow a parabolic arcsimilar to that of the walls of the inner and outer caps. The rib 701tapers in thickness from nothing at the top rim 704 of the inner cap750-1 b to its thickest point at the base 704 of the inside wall of theouter cap 750-1 a. Preferably the rib 701 is thinner at the top rim 707of the inner cap 750-1 b than at the base 704 of the outer cap 750-1 a.Preferably the rib 701 gets progressively thicker from the top rim 707of the inner cap 750-1 b to the base 704 of the outer cap 750-1 a. Thethickness, taper and progression of thickness may vary from rib to rib.The rib 701 extends into the air gap 710 but does not completely fillthe air gap 710.

Surprisingly, it has been found that the addition of the rib or ribs 701helps to improve the seal created in the patient's nostrils when in use.The ribs further provide strengthening of the inner cap 750-1 b. Theinner cap 750-1 b folding back in the stalk 750-3 can reduce theeffectiveness of the seal created by the pillow portions 700, with theuser's nostrils, when in use. The addition of the rib or ribs 701reduces and helps to eliminate the folding of the inner cap 750-1 b backinto the stalk 750-3 when there is load on it from the user's nostrilspushing against the inner and outer caps. The addition of the ribs 701provides the surprising effect of improving the seal created by thepillow portions 700 when in use.

The rib or ribs 701 also strengthen the inner cap 750-1 b and providerigidity to the inner cap 750-1 b. This provides more support to theouter cap 750-1 a and prevents the outer cap from deforming too muchwhen depressed by a user's nostril in use. The ribs help to control orlimit the amount of deformation the inner and outer caps 750-1 b and750-1 a, undergo when in use. The rib or ribs 701 help to make the outerand inner cap more rigid and hence create a better seal with a user'snostrils.

The addition of the rib or ribs 701 maintains the flexibility of theouter cap 750-1 a or inner cap 750-1 b while providing strength andsupport against permanent bending and deformation to the inner cap 750-1b and outer cap 750-1 a. This flexibility of the outer cap 750-1 a orthe inner cap 750-1 b or both makes the pillow portions 700 suitable foruse with a wide range of users and a variety of nostril shapes since theinner or outer cap or both can flex to take the shape of any nostril andcreate a substantial seal with the nostril.

A further embodiment of the pillow portions is shown in FIGS. 8a, 8b and8c . In this variation, the pillow portions are shown as being used withthe pillow gasket portion 350-2 (although as outlined above, these couldbe used with pillow gasket portion 250-2 or pillow gasket portion450-2).

As can be seen from FIGS. 8a-8c this embodiment is made up of the firstgeneral form of the pillow portion as described above. The specificvariations of this embodiment will be described below.

In the preferred form of this embodiment the walls of the inner cap850-1 b and the outer cap 850-1 a taper in cross sectional thickness, asbest seen in FIG. 8c . The wall of the inner cap 850-1 b is thicker atthe base of the inner cap 805 than at the rim 807 of the inner cap 850-1b. The wall of the outer cap 850-1 a is thicker at the base 804 of theouter cap 850-1 a than at the rim 806 of the outer cap 850-1 a.Alternatively the thickness of the walls of the outer 850-1 a and inner850-1 b caps may be uniform thickness. As a further alternative the wallthickness of one of the walls may taper while the other wall does not,for example the wall thickness of the wall of the outer cap 850-1 a maytaper while the wall thickness of the inner cap 850-1 b may remainconstant. The inner and outer caps flare upwards and outwards in asimilar manner as has already been described for the previous embodimentof FIG. 7.

There is a cavity or air gap 810 formed between the outside surface ofwall of the inner cap 850-1 b and the inside surface of the wall of theouter cap 850-1 a. The cavity 810 is out of the direct air path of thecaps 850-1 a and 850-1 b, meaning the cavity 810 is not formed in thepath of the stream of gases being delivered to the user.

The cavity 810 between the inner 850-1 b and outer cap 850-1 a containsat least one but preferably a pair (or more) of ribs 801 that extendinto the cavity 810. The rib or ribs 801 may be positioned at regular ordiffering intervals around the perimeter of the outer surface of thewall of the inner cap 850-1 b or the inner surface of the wall of theouter cap 850-1 a. The rib or ribs 801 can be attached or formedintegral to the outer surface of the wall of the inner cap 850-1 b or tothe inner surface of the wall of the outer cap 850-1 a or both.Preferably the rib 801 is positioned on the inside surface of the wallof the outer cap 850-1 a. The rib or ribs 801 can be positioned at anyposition along the inside surface of the wall of the outer cap 850-1 a.Preferably the ribs 801 are equally spaced along the perimeter of theinner surface of the wall of the outer cap 850-1 a. Alternatively thespacing between successive ribs could vary and could be irregular.

Preferably the rib or ribs 801 extend from the top rim 806 of the insidesurface of the wall of the outer cap 850-1 a or are formed along theinside surface of the wall of the outer cap 850-1 a and preferablyextend all the way to the common base 804 of the inner and outer caps.The rib conforms to the shape of the cavity 810 and follows the generalcurve of the walls of the inner cap 850-1 b and outer cap 850-1 a.

The rib or ribs 801 generally curves outwards from the rim 806 anddownwards to the outer edge of the rim 807 of the inner cap 850-1 b,where it merges with the rim 807, with the rib 801 then extendingdownwards to the common base 804 merged with or at least contacting theinner cap 850-1 b all the way along the outer wall of the inner cap850-1 b.

Surprisingly, it has been found the addition of the rib or ribs 801helps to reduce or eliminate the folding of the inner cap 850-1 b backon the stalk 850-3. This allows a more effective seal to form with theuser's nostrils when in use and stops the inner cap 850-1 b fromblocking the exit orifice and leads to the correct amounts of therapygases being delivered to the user.

The rib or ribs 801 are also intended to add strength to the outer cap850-1 a to stop the outer cap or the rim 806 of the outer cap fromcompletely collapsing onto the inner cap 850-1 b, the stalks 850-3 orthe exit orifice. The rib or ribs 801 provide strengthening by actinglike a splint and resisting the forces exerted on the inner and outercaps when the pillow portions 800 are in use. The addition of the rib orribs 801 provides the advantage of making it easier to correctly fit thepillow portions 800 into a user's nostrils. The addition of a rib orribs 801 adds strength but also maintains some degree of flexibility ofthe outer cap 850-1 a. The flexibility of the outer cap 850-1 a allowsthe outer cap 850-1 a to flex and conform to the shape of a user'snostrils in order to create an effective seal with the user's nostrils.

The inner cap 850-1 b without any rib or ribs 801 may often collapsewhen in use and cover or partially cover the exit orifice of the innercap 850-1 b. The collapsing of the inner cap may result in pressure dropacross the pillow portion 800 during the exhale cycle of the user,resulting in an increase in the effort needed by the user to exhale.This increased effort by the user may cause harm to the user and coulddamage the user's respiratory system.

Surprisingly it has been found that the addition of the rib or ribs 801can strengthen the inner cap 850-1 b and reduces or minimises thecollapse of the inner cap 850-1 b on to itself because the rib 801 actslike a splint and absorbs the forces exerted upon the inner cap. If theinner cap begins to collapse or fold the rib resists that movement andexerts an opposite force to force the inner cap 850-1 b to maintain itsposition. This provides the advantage of being comfortable for the usersince the user may not need to use as much effort to exhale.

A further embodiment of the pillow portions is shown in FIGS. 9a, 9b and9c . In this variation, the pillow portions are shown as being used withthe pillow gasket portion 350-2 (although as outlined above, these couldbe used with pillow gasket portion 250-2 or pillow gasket portion450-2).

As seen in FIGS. 9a-9c this embodiment is made up of the first generalform of the nasal pillow portion 9 (described above). The specificvariations of this embodiment are described below.

In the preferred form of this embodiment the walls of the inner cap950-1 b and the outer cap 950-1 a taper in cross sectional thickness asbest seen in FIG. 9c . The wall of the inner cap 950-1 b is preferablythicker at the base 905 of the inner cap 950-1 b than at the rim 907 ofthe inner cap 950-1 b. The wall of the outer cap 950-1 a is preferablythicker at the base 904 of the outer cap 950-1 a than at the rim 906 ofthe outer cap 950-1 a. Alternatively the thickness of walls of the inner950-1 b and outer 950-1 a caps may be uniform. As a further alternativethe thickness of the wall of one of the caps may taper while thethickness of the other cap may remain uniform—for example the thicknessof the wall of the inner cap 950-1 b may taper while the thickness ofthe wall of the outer cap 950-1 a may be constant. There is a cavity 910or air gap formed between the outer cap 950-1 a and the inner cap 950-1b (except where they are connected at their bases to the stalk and toeach other). This cavity 910 is not in the direct air path of the streamof gases, as best seen in FIG. 9 c.

The inside surface of the wall of the outer cap 950-1 a contains atleast one and preferably two ribs 901. Alternatively the inside surfaceof the wall of the outer cap may contain 3 or more ribs 901. Preferablythe rib or ribs 901 are located along the inside surface of the wall ofthe outside cap 950-1 a, extending from the rim 906 into the cavity 910between the inner 950-1 b and outer cap 950-1 a and connecting to eitherthe base 904 of the outer cap 950-1 a or to the base 905 of the innercap 950-1 b as shown in FIG. 9 c.

Preferably the rib partially fills the volume of the cavity 910,extending and curving outwards from the rim 906 of the outer cap 950-1 aand into the airgap or cavity 910, but not contacting the outer surfaceof the inner cap 950-1 b when the caps are in a non-deformed state.There is a gap 911 between the rib 901 and the outer surface of the wallof the inner cap 950-1 b, as seen in FIG. 9b . Preferably the ribextends between one quarter and three quarters of the way across theairgap 911 from the inner surface of the outer cap 950-1 a to the outersurface of the inner cap 950-1 b.

If a plurality of ribs 901 is used the ribs 901 may be positioned atregular or differing intervals around the perimeter of the inner orouter cap. The distance between ribs 901 may very from rib to rib, forexample the distance between a first pair of ribs may be similar ordifferent to the distance between a second pair of ribs 901. The ribspreferably are thicker at the base of the rib than at the top of therib, as seen in FIG. 9c . This means the ribs may be thicker at the base904 of the outer cap 950-1 a or at the base 905 of the inner cap 950-1b, than at the rim 906 of the outer cap 950-1 a. The ribs 901 may allhave the same rate of change of thickness or the rate of change ofthickness may vary from rib to rib. Alternatively the ribs may all bethe same thickness or the ribs may be thicker at the rim 906 of theouter cap 950-1 a and thinner at the base 904 or 905 of the outer orinner cap respectively. Each of the arrangements described above mayvary between each individual rib feature. Furthermore, the width(side-side or horizontal dimension through the rib) may vary—i.e. not beconstant. The rib width could be greater at the base than at the top ofthe rib, for example.

Surprisingly, it has been found that the addition of the rib 901 resultsin strengthening the outer cap. The addition of the rib 901 helps to addstiffness to the outer cap 950-1 a and hence the outer cap does notcollapse completely and hold its shape better. Since the outer cap 950-1a can hold its shape, this provides the advantage that the pillowportions 900 can be correctly fitted into a patient's nostrils and thepillow portions, in particular the outer surface of the wall of theouter cap forms a better seal with a user's nostrils. The rib 901 actsto support the outer cap and resists forces applied to the outer cap950-1 a as the pillow portions 900 are inserted into a user's nostrils.

The flexibility of the outer cap 950-1 a allows the outer cap to deformenough to fit into a nostril and the rib ensures that the outer cap950-1 a has sufficient strength to assist in providing a seal with theuser's nostrils.

It has also surprisingly been found that the tapered rib thickness helpsto provide the outer cap 950-1 a with maximum strength and rigiditywithout compromising flexibility of the outer cap 950-1 a. Thecombination of flexibility and rigidity allow the pillow portion 900 toform a substantial seal and a correct fit within the user's nostrils.This can provide the advantage of a more effective therapy beingdelivered to a user.

A further embodiment of the pillow portions is shown in FIGS. 10a, 10b ,and 10 c. In this variation, the pillow portions are shown as being usedwith the pillow gasket portion 350-2 (but as outlined above, the pillowportions may be used with the pillow gasket portion 250-2 or pillowgasket portion 450-2).

As seen in FIGS. 10a-10c , this embodiment of the nasal pillows isgenerally made up of the first general form of the pillow portion(described above). However, specific to this embodiment, the inner cap1050-1 b extends above the outer cap 1050-1 a, in order to provide abetter fit in the users nostrils and helps to provide a better seal, asshown in FIG. 10c . Further variations of this embodiment will bedescribed below.

In the preferred form of this embodiment the walls of the inner cap1050-1 b and the outer cap 1050-1 a taper in cross sectional thickness,as best seen in FIG. 10c . The wall of the inner cap 1050-1 b ispreferably thicker at the base 1005 of the inner cap 1050-1 b than atthe rim 1007 of the inner cap 1050-1 b. The wall of the outer cap 1050-1a is preferably thicker at the base of the 1004 of the outer cap 1050-1a than at the rim 1006 of the outer cap 1050-1 a. Alternatively the wallthickness of the inner cap 1050-1 b and the outer cap 1050-1 a may beuniform. As another alternative the wall thickness of the inner andouter caps may be equal to each other—meaning the wall of the inner cap1050-1 b is the same thickness as the wall of the outer cap 1050-1 a.Further to this the wall cross section of the inner and outer cap may beidentical to each other. As a further alternative the thickness of thewall of one of the caps may taper while the thickness of the other capwall may be uniform—for example the thickness of the wall of the innercap 1050-1 b may taper while the thickness of the wall of the outer cap1050-1 a may be uniform.

The cap 1050-1 includes at least one “rib” feature within the cap.Preferably this rib feature is a solid fin 1001 that passes through theentire cap 1050-1. Preferably the fin 1001 is a thin element withparallel sides which passes in a planar fashion across the cap 1050-1.The fin 1001 could also be described as passing diametrically across thepillow section, although it should be noted that ‘diametrically’ as itis used in this context and in the specification generally should not betaken as meaning that the caps are circular. The fin 1001 joins theinner cap 1050-1 b with the outer cap 1050-1 a, as seen in FIGS. 10a and10b . Preferably part of the fin 1001 lies within the path of the streamof gases delivered to the user or patient, as seen in FIG. 10a . The fin1001 extends from the rim 1006 of the outer cap 1050-1 a to the pointwhere the cap 1050-1 joins the stalk 1050-3, as best seen in the leftcap of FIG. 10b . The fin 1001 extends from the rim 1006 of the outercap 1050-1 a to the point where the bases of the inner 1050-1 b andouter 1050-1 a caps join each other. The fin 1001 preferably fills theair gap 1010 completely, at the cross-section X. The fin 1001 extendsfrom one side of the cap to the other side of the cap, meaning the fin1001 extends across the entire diameter of the cap 1050-1, as best seenin FIG. 10b . Preferably the fin 1001 follows the contours of theoverall cap shape. Preferably the fin 1001 extends vertically from theinner cap 1050-1 b to the outer cap 1050-1 a.

As described above, in the preferred embodiment the sides of the fin arestraight to form the planar fin. Alternatively the fin 1001 could becurved in shape (not shown) as it passes from one side of the pillowsection to the other, instead of being straight as shown in FIGS. 10aand 10b , and form a gentle curved plane, preferably an invertedparabola as it passes through the entire cap 1050-1. As a furtheralternative the fin 1001 could be even angled about a central or offsetvertex point. For example, the central vertical axis of the exit orifice1020 of the cap 1050-1, as seen in FIG. 10a , or alternatively the fin1001 may be offset about the vertex point. The vertex point preferablyis situated in the middle of the exit orifice 1020 of the cap 1050-1.However, the vertex point may be at any point along the width of the cap1050-1.

As described above, the fin 1001 is parallel-sided, with the sidesaligned vertically in use, and thin. However, in alternativeembodiments, the fin 1001 can taper in thickness. The fin 1001 can bethicker at the base of the inner and outer caps than at the rim 1006 ofthe outer cap 1050-1 a. Alternatively the fin 1001 may be thicker at therim 1006 of the outer cap 1050-1 a than at the base of the caps. Thistapering thickness helps to direct airflow from the stalks out of theorifice 1020 and out of the cap 1050-1. The addition of the fin and thetapered cross section of the fin help in reducing the velocity of thedelivered gases to a velocity that is comfortable for a user to acceptthe stream of gas. The possible reduction in velocity may also helpprevent air jetting effects that can annoy or damage the nasal passagesof a user. The fin 1001 also helps to maintain a low level of pressuredrop across the nasal interface when the interface is in use. This againincreases comfort for the user.

As a further alternative the fin 1001 may have uniform thickness alongits profile. In the preferred form the cap 1050-1 only includes one fin1001 per cap 1050-1, but each cap may include multiple fins 1001 spacedat varying or constant distances from one another. The fin is preferablymade from the same materials as the cap portion 1050-1.

Surprisingly it has been found that adding a fin 1001 to the cap 1050-1results in strengthening the entire cap 1050-1 structure. The additionof the fin 1001 adds stiffness to the cap 1050-1 and strengthens boththe inner and outer caps. The fin helps to prevent the inner and outercaps from folding and permanently deforming in use. Since the cap 1050-1is stiffer and can resist permanent deformation, this provides theadvantage that the cap 1050-1 and hence the pillow portions 1000 can becorrectly fitted into a patient's nostrils.

While strengthening the cap 1050-1 structure the addition of the fin1001 still allows the cap to maintain flexibility on either side of thefin 1001. This flexibility allows the cap 1050-1 to elastically deformas the cap conforms to the nostrils of the user and allows the cap toprovide a better seal with the nostrils of the user.

It has also surprisingly been found that the addition of the fin 1001helps to prevent the collapse of the outer cap 1050-1 a into the path ofthe stream of gases and closing of the orifice 1020 of the caps. Theclosing or partial closing of the orifice 1020 increases pressure dropacross the cap 1050-1 and increases the effort needed by the user orpatient to exhale through the nasal interface. The addition of the fin1001 aids in preventing the outer cap 1050-1 a from collapsing into theorifice 1020 and into the path of the stream gases, thus improvingcomfort and safety for the user. The fin 1001 also provides theadvantage of delivering more effective therapy since the addition of thefin 1001 provides a better seal and helps in preventing the outer cap1050-1 a from collapsing into the path of the stream of gases and fromsealing up the orifice 1020.

A further embodiment of the pillow portion is shown in FIGS. 11a, 11band 11c . In this variation, the pillow portion is shown as being usedwith the pillow gasket portion 350-2 (although as outlined above, thepillow portion could be used with pillow gasket portion 250-2 or pillowgasket portion 450-2). In this embodiment the pillow section is formedfrom the pillow portions and the pillow gasket portion.

As seen in FIGS. 11a-11c this embodiment is made up of the first generalform of the pillow portion (described above). Specific variations ofthis embodiment will now be described.

In the preferred form of this embodiment the walls of the inner cap1150-1 b and the outer cap 1150-1 a taper in cross sectional thicknessas best seen in FIG. 11c . The walls of the inner cap 1150-1 b and theouter cap 1150-1 a are thicker at the lower end. The wall of the outercap 1150-1 a is thicker at the base 1104 of the outer cap 1150-1 a thanat the rim 1106 of the outer cap 1150-1 a. The wall of the inner cap1150-1 b is thicker at the base 1105 of the inner cap 1150-1 b than atthe rim 1107 of the inner cap 1150-1 b. Alternatively the thickness ofthe walls of the inner and outer cap may be constant or the wallthickness of one of the walls may taper while the wall thickness of theother wall may remain constant—for example the thickness of the wall ofthe outer cap 1150-1 a may taper while the thickness of the wall of theinner cap 1150-1 b may remain constant. As another alternative the wallof one or both caps may be thicker at the top near the rim than at thebase.

The inner cap 1150-1 b is shaped such that a recess 1130 is created atthe point where the inner cap 1150-1 b attaches to the top of the stalk1150-3. The recess is formed due to the shape of the inner cap and theflare of the inner cap, as best seen in FIG. 11c . The recess 1130 is anair gap formed in the path the stream of gases follow as they flow fromthe gasket portion, through the pillow portion and out through theorifice 1120 in the pillow portion. The recess 1130 follows theperimeter of the inner cap 1150-1 b. An air gap 1110 is formed betweenthe inner wall of the outer cap 1150-1 a and the outer wall of the innercap 1150-1 b, best seen in FIG. 11c . The air gap 1110 is not formed inthe path of the gases being delivered to the user.

The inner surface of the inner cap 1150-1 b includes at least one, butpreferably a plurality of ribs 1101. The rib or ribs 1101 are preferablyhoused within the recess 1130. Preferably the rib 1101 is housed onlywithin the recess 1130. However, alternatively the rib 1101 may behoused within the recess 1130 and extend through the inner cap 1150-1 bto the base 1104 of the outer cap 1150-1 a. In a further alternative therib 1101 may be formed of two sections, a first section housed withinthe recess 1130 and a section housed within the lower part of the airgap 1110.

If a plurality of ribs 1101 is used the ribs 1101 may be positioned atregular intervals around the perimeter of the recess 1130, the ribsbeing attached to the inside surface of the inner cap 1150-1 b.Alternatively the ribs 1101 may be positioned at varying intervalsaround the perimeter of the inner cap 1150-1 b and within the recess1130 which also runs the perimeter of the inner cap 1150-1 b. Thespacing between ribs may also very from rib to rib. Preferably all theribs 1101 are of the same thickness and width. Alternatively each rib1101 may be of different thickness and width from each other rib 1101.

The rib 1101 follows the same profile as the stalk and the inner surfaceof the inner cap 1150-1 b, so as to provide a smooth passageway forgases to pass through the pillow portion 1100, as best seen in FIG. 11c.

Surprisingly it has been found that the addition of the rib 1101 intothe recess 1130 formed within the inner cap 1150-1 b provides severaladvantages. Firstly the addition of the rib reduces and helps to stopthe inner cap 1150-1 b from folding into the stalk 1150-3. The inner cap1150-1 b folding back into the stalk 1150-3 causes the stalk and hencethe entire cap 1100 structure to deform or collapse, thus reducing theeffectiveness of the seal created with the nose. Sealing with nasalcavities is vital for delivering a stream of gases and allows foreffective therapy for the patient or user. The addition of the ribs 1101helps in creating an effective seal with the users' nostrils or nares.

It has also surprisingly been found that the addition of a rib or ribs1101 into the recess 1130 adds strength to the inner cap 1150-1 b thatin turn provides added support for the outer cap 1150-1 a when thepillow portion 1100 is in use and the outer cap 1150-1 a is placed intoa users' nostril. This improves the effectiveness of the seal createdbetween the outer cap 1150-1 a and the users' nostril. It has alsosurprisingly been found that the addition of the rib 1101 allows theouter cap 1150-1 a to be substantially flexible while providing supportand strength to the inner cap 1150-1 b. The flexibility of the outer cap1150-1 a and the support added to the outer cap 1150-1 a by the rib 1101allows the outer cap 1150-1 a to seal with a variety of differentnostril shapes. It allows the pillow portion 1100 to be used by avariety of users.

An further embodiment of a pillow portion 1200 is shown in FIG. 12. Acap 1250-1 forms part of the pillow portion 1200 that is preferably usedwith the pillow gasket 350-2 (not shown). The pillow portion 1200 issimilar to pillow portion 800, with specific differences as outlinedbelow. As outlined above in the specification, the pillow portion 1200could be used with pillow gasket portion 250-2 or pillow gasket portion450-2. In this embodiment the pillow section is formed from a pair ofthe pillows portions 1200 and a pillow gasket portion such as gasketsection 350-2 (but as outlined above, the pillow portions may be usedwith the pillow gasket portion 250-2 or pillow gasket portion 450-2).FIG. 12 only shows one of the pair of pillow portions.

FIG. 12 shows that this embodiment is made up of the first general formof the pillow portion (described above). The specific variations of thepillow portion are described below.

In the preferred form of this embodiment the walls of the inner cap1250-1 b taper in cross sectional thickness as best seen in FIG. 12. Thewalls of the inner cap 1250-1 b are thicker at the rim 1207 of the innercap 1250-1 b than at the base 1205 of the inner cap 1250-1 b. In thepreferred form the inner cap 1250-1 b also has a sharp edge at the rim1207 of the inner cap 1250-1 b, as seen in FIG. 12. In an alternate formthe rim 1207 of the inner cap 1250-1 b may be slightly rounded toimprove manufacturability and comfort for the user when the pillowportion 1200 is in use. In the preferred form the cross sectionalthickness of the inner cap 1250-1 b wall may be thicker than the crosssectional thickness of the outer cap 1250-1 a wall. This means thethinnest part of the inner cap 1250-1 b wall may be thicker than theouter cap 1250-1 a wall. The wall of the outer cap 1250-1 a may beconstant in thickness or may taper in thickness. In the preferred formthe wall of the outer cap 1250-1 a has a constant cross sectionalthickness, as seen in FIG. 12. Alternatively the cross sectionalthickness of the wall of the outer cap 1250-1 a may be thicker at thebase 1204 of the outer cap 1250-1 a and thinner at the rim 1206 of theouter cap 1250-1 a. As a further alternative the cross sectionalthickness of the wall of the outer cap 1250-1 a may be thicker at therim 1206 than at the base 1204 of the outer cap 1250-1 a.

Surprisingly it has been found that having a larger cross sectional wallthickness at the rim 1207 of the inner cap 1250-1 b helps to improve thestrength of the inner cap 1250-1 b and the rim 1207 section of the innercap 1250-1 b. A common problem that occurs when the pillow portion 1200is in use is that the outer cap 1250-1 a is depressed by the user'snostrils. The outer cap 1250-1 a can bear onto the inner cap 1250-1 band cause the inner cap to collapse and possibly block the path of thegases being delivered to the user through the pillow portion 1200. Thethicker rim 1207 of the inner cap 1250-1 b helps to prevent the rim 1207from collapsing when the rim 1207 is depressed by the outer cap 1250-1a. Preventing the inner cap 1250-1 b from blocking the gases fromexiting the pillow portion 1200 helps to prevent an increase in thepressure drop across the pillow and prevents the user from exertingexcessive effort to exhale through the pillow portion 1200. Thisparticular advantage leads to the delivery of more effective therapy.

It has also surprisingly been found that a thicker wall section at therim 1207 of the inner cap assists in maintaining the airway 1240 open,which can partially collapse when the user or patient is exhaling. Thethicker wall section adds strength to the inner cap 1250-1 a, inparticular the rim section 1207 of the inner cap 1250-1 a and helps tostop the rim section or the inner cap 1250-1 a from collapsing. It hasalso surprisingly been found that the thicker rim 1207 section resultsin the outer cap 1250-1 a and inner cap 1250-1 b being substantiallyflexible and supple allowing the pillow portion 1200 to form aneffective seal with the user's nostril.

A further embodiment of a pillow portion 1300 is shown in FIG. 13. A cap1350-1 forms part of the pillow portion 1300 that is preferably usedwith the pillow gasket 350-2 (not shown) as one of a pair of pillowportions. The pillow portion 1300 is similar to pillow portion 800, withspecific differences as outlined below. As outlined above in thespecification, the pillows portion 1300 could also be used with pillowgasket portion 250-2 or pillow gasket portion 450-2. FIG. 13 shows onepillow portion.

As seen from FIG. 13, this embodiment is made up of the first generalform of pillow portion (described above). The specific variations ofthis embodiment are described below.

In the preferred form of this embodiment the cross sectional thicknessof the wall of the inner cap 1350-1 b tapers in thickness, as seen inFIG. 13. The wall of the inner cap 1350-1 b is thicker at the base 1305of the inner cap 1350-1 b than at the rim 1307 of the inner cap 1350-1b. Alternatively the wall of the inner cap 1350-1 b may be constant incross-sectional thickness. In a further alternative form the wall of theinner cap 1350-1 b may be thinner in cross sectional thickness at thebase 1305 and thicker at the rim 1307. In the preferred form the crosssectional thickness of the wall of the outer cap 1350-1 a may beconstant along the entire outer cap 1350-1 a. However, in an alternativeform the wall thickness of the outer cap 1350-1 a may taper inthickness—for example the wall of the outer cap may be thicker at thebase 1304 of the outer cap 1350-1 a and thinner at the rim 1306 of theouter cap 1350-1 a.

Surprisingly it has been found that the tapering cross sectional wallthickness of the inner cap 1350-1 b assists in improving the overallstiffness and in particular the flexural stiffness of the inner cap. Thetapering cross sectional wall thickness of the inner cap 1350-1 b alsohelps to strengthen the inner cap 1350-1 b walls. A common problem thatmay occur when the pillows are in use is that the outer cap 1350-1 adepresses as it tries to conform to the shape of the user's nostril inorder to form a seal. The outer cap 1350-1 a can bear on the inner cap1350-1 b as it depresses. The added stiffness from the tapered crosssection of the inner cap 1350-1 b helps to prevent the inner cap 1350-1b from collapsing into the airway 1340 (path of gases) when the innercap 1350-1 b is depressed by the outer cap 1350-1 a. This helps toprevent the inner cap 1350-1 b from collapsing and blocking the exit ofgases from the pillows. Blocking the exit of the gases from the pillowscan increase the pressure drop across the pillows 1300 and increase theeffort required by a patient to breath out of the pillow portion 1300.The added stiffness of the inner cap 1350-1 b wall also helps to preventthe inner wall from collapsing and blocking the exit of gases thusreducing the effort required by a patient to breath out through thepillow portion 1300 and reduces the pressure drop across the pillowportion 1300. This leads to more effective therapy delivered to apatient and makes the pillow portion 1300 and system more comfortable touse.

In the preferred form both the rim 1307 of the inner cap 1350-1 b andthe rim 1306 of the outer cap 1350-1 a also include a round bead 1301extending around the perimeter of the rims, as seen in FIG. 13. Theouter cap rim 1306 has a first bead 1301 a extending inwards and runningaround the perimeter, while the inner cap rim 1307 has another, secondseparate bead 1301 b extending inwards and running around the perimeter.Alternatively only one of the caps may have a bead 1301 extending aroundits rim—for example on the inner cap 1350-1 b may have the bead 1301extending around its rim 1307 or vice versa. Preferably the bead isformed integral to the inner and outer caps. The beads are formed aspart of the manufacturing process.

Surprisingly it has been found that the addition of the beads 1301 a and1301 b strengthens the rims 1306, 1307 of the outer and inner caps andadds stiffness to the rims 1306, 1307. As the patient exhales throughthe caps 1350-1 a, 1350-1 b, the caps or at least part of the caps canpartially collapse. The inner cap or outer cap or both caps can alsopartially collapse when the cap section 1350-1 is depressed into auser's nostrils during the fitting of the pillow portion 1300. Theincreased stiffness of the rims 1306, 1307 of the inner and outer capsprevent the rims from collapsing as the patient is exhaling or as thepillow portion 1300 is being fitted into a patient's nostrils thusmaintaining the airway 1340 in an open position. This can also reducethe effort the patient requires as he or she exhales through the pillowportion 1300, leading to increased comfort and more effective therapyfor the patient. Adding a bead to both the inner and the outer rims hasbeen found to have this surprisingly beneficial effect.

It has also surprisingly been found that the addition of the beads 1301a and 1301 b in combination with the tapering cross section of inner cap1350-1 b results in the inner cap 1350-1 b and outer cap 1350-1 a inbeing flexible and supple to allow the pillow portion to form aneffective seal with the user's nostril and deliver effective therapy tothe user, and yet having a structural stability and strength sufficientto help prevent collapse in use.

A further embodiment of a pillow portion 1400 is shown in FIG. 14. A cap1450-1 forms part of the pillow portion. The cap 1450-1 is preferablyused with the pillow gasket 350-2 (not shown), but can be used witheither of the other two pillow gaskets specifically described above, orany other suitable pillow gasket. The pillow portion 1400 has similarfeatures to pillow portion 800, with specific differences as outlinedbelow. As outlined above in the specification, the pillows portion 1400could be used with pillow gasket portion 250-2 or pillow gasket portion450-2. FIG. 14 shows one pillow portion.

As seen from FIG. 14, this embodiment is made up of the first generalform of the pillow portion (described above). The specific variations ofthis embodiment will be described below.

In the preferred form of this embodiment the walls of the inner cap1450-1 b and the outer cap 1450-1 a taper in cross sectional thicknessas best seen in FIG. 14. The wall of the inner cap 1450-1 b ispreferably thicker at the base 1405 of the inner cap 1450-1 b than atthe rim 1407 of the inner cap 1450-1 b. The wall of the outer cap 1450-1a is preferably thicker at the base 1404 of the outer cap 1450-1 a thanat the rim 1406 of the outer cap 1450-1 a. Alternatively the thicknessof walls of the inner 1450-1 b and outer 1450-1 a caps may be uniform.As a further alternative the thickness of the wall of one of the capsmay taper while the thickness of the other cap may remain uniform—forexample the thickness of the wall of the inner cap 1450-1 b may taperwhile the thickness of the wall of the outer cap 1450-1 a may beconstant. There is a cavity 1410 or air gap formed between the outer cap1450-1 a and the inner cap 1450-1 b (except where they are connected attheir bases to the stalk and to each other). This cavity 1410 is not inthe direct air path of the stream of gases, as best seen in FIG. 14.

In the preferred form of this embodiment a continuous flange 1401extends upward from the point where the base 1304 of the outer cap1450-1 a meets the base 1305 of the inner cap 1450-1 b. The flangeextends around the perimeter of the cap 1450-1. The flange extendsupwards from the base into the air gap 1410 between the inner and theouter caps as seen in FIG. 14. In the preferred form the flange 1401 isgenerally approximately triangular in cross section. Alternatively theflange may be of any other appropriate cross section—for example arectangular cross section or oval. The cross sections described here areonly examples and should not be construed as limiting in any way.Preferably the flange 1401 extends upward into the air gap 1410,anywhere up to half the height of the inner cap 1450-1 b. Morepreferably the flange 1401 extends upward into the air gap 1410, oneseventh to one quarter of the total height of the inner cap 1450-1 b.Preferably the height of the flange 1401 is constant around theperimeter of the inner cap 1450-1 b. In an alternative form the flange1401 height may vary along the perimeter of the inner cap 1450-1b—meaning the height of the flange 1401 may vary at various points alongthe perimeter of the inner cap 1450-1 b. This variation in the height ofthe flange aims to strategically add strength to the outer cap 1450-1 ain specific areas that are weaker. Therefore, for example the height ofthe flange may be increased at the weaker points along the outer cap1450-1 a to strengthen them. In still further embodiments, there may begaps in the flange around the perimeter—that is, the flange isdiscontinuous around its perimeter.

Surprisingly it has been found that the addition of the flange 1401 actsto strengthen the lower parts of the outer cap 1450-1 a and helps addrigidity and support to the lower part of the outer cap 1450-1 a. Theaddition of the flange also allows the outer cap 1450-1 a to exert alarger force on a patient's nostril when the caps 1450-1 and pillowportion 1400 are in use, due to the additional rigidity and strengthadded to the lower portion of the outer cap 1450-1 a by the flange 1401.This helps to improve the seal formed between the outer cap 1450-1 a andthe user's nostril allowing for more effective therapy to be delivered.The flange also acts as a support for the outer cap 1450-1 a—for exampleas the outer cap 1450-1 a bends and is depressed while being fitted intoa user's nostrils the flange acts against the bending of the outer cap1450-1 a and thus allows the outer cap 1450-1 a to exert a larger forceagainst the nostril of the user to form a more effective seal.

It has also surprisingly been found that by adding the flange 1401, thisallows the upper part of the outer cap 1450-1 a to maintain flexibility,while providing strength and rigidity for the lower part of the outercap 1450-1 a. The flexibility of the upper part of the outer cap 1450-1a allows the upper part of the outer cap 1450-1 a to flex and bend inorder to conform to the shape of a user's nostril and form an effectiveseal with the nostril. The flexibility of the upper part of the outercap 1450-1 a allows the pillow portion 1400 to be used with a variety ofusers and allows the pillow portion to conform to a variety of nostrilshapes.

FIG. 15 shows a further embodiment of a pillow portion 1500. Thisembodiment is substantially similar to the embodiment described abovewith respect to FIG. 13. This embodiment is generally made up of thefirst general form of the pillow portion.

This embodiment is made up of the first general form of the pillowportion (described above). The eleventh embodiment also includes a bead1501 a on the rim 1506 of outer cap 1550-1 a and a bead 1501 b on therim 1507 of the inner cap 1550-1 b. This is very similar to embodimentnine described above.

The key difference between this embodiment and the embodiment shown inFIG. 13, is that in this embodiment, the inner cap wall has a uniformcross sectional thickness. The beads 1501 a and 1501 b extending fromthe rims 1506 and 1507 are substantially similar in shape and propertiesto the beads 1301 a and 1301 b described in the ninth embodiment.

Surprisingly it has been found that adding the beads to both the innerand the outer caps provides additional strength and stiffness, inparticular flexural stiffness to the rims 1506, 1507 of the outer andinner caps respectively. A patient or user generally inhales and exhalesthrough the nasal pillow portions 1500 when in use. A common problemthat can occur is the rim of the outer cap or inner cap or both cancollapse partially and partially or completely block the airway 1540 thetherapy gases pass through. This can lead to increased pressure dropacross the nasal pillow portion 1500 and cause the user to exert extraeffort to exhale. The bead 1501 strengthens the rims 1506, 1507 of theouter and inner caps and helps to prevent the rims from collapsing intothe airway 1540 and closing the airway 1540. This allows the airway 1540to stay open and thus the user exerts less effort to exhale through thenasal pillow portion 1500. This makes the nasal pillows more comfortableto use for a patient as the patient can breathe naturally and does nothave to exert extra effort to exhale through the pillows portion 1500.The rims 1506, 1507 can also collapse partially or completely into theairway 1540 as the cap 1550-1 is depressed while fitting the cap 1550-1into a patient's nostrils. The bead 1501 reinforces the rims 1506, 1507and may stop them from collapsing while the cap 1550-1 is being fittedinto a patient's nostril allowing for a more comfortable fit and a moreeffective seal being formed.

A further embodiment of a pillow portion 1600 is shown in FIG. 16. A cap1650-1 forms part of a pillow portion 1600 that is preferably used asone of a pair of pillow portions with the pillow gasket 350-2 (notshown). The pillow portion 1600 is similar to pillow portion 800, withspecific structural differences as outlined below. As outlined above inthe specification, the pillows portion 1600 could be used with pillowgasket portion 250-2 or pillow gasket portion 450-2. FIG. 16 shows onlyone nasal pillow portion

As can be seen from FIG. 16, this embodiment is made up of the firstgeneral form of the pillow portion (described above). The specificvariations of the pillow portion of this embodiment are described below.

In the preferred form the cap 1650-1 is wider at the base than the stalk1650-3. The outer 1650-1 a and inner 1650-1 b caps merge at their bases,with the base extending outwards almost perpendicular to the axis of thestalk 1650-3 before angling upwards and inwards. The shape of the innerand outer caps allows the caps to form a substantial seal with thenostril of the user, when in use. The inner and outer caps flare upwardsand outward in a similar manner as has already been described for theembodiments shown in FIGS. 7, 8 and 14.

In the most preferred form the cross sectional thickness of the wall ofthe inner cap 1650-1 b is uniform along the height of the inner cap1650-1 b, as seen in FIG. 16. In a less preferred form the thickness ofthe wall of the inner cap 1650-1 b may taper in any direction. In thepreferred form the cross sectional thickness of the wall of the outercap 1650-1 a is uniform along the length of the outer cap 1650-1 a asseen in FIG. 16. Alternatively the cross sectional thickness of theouter cap 1650-1 a wall may vary along the height of the outer cap1650-1 a—meaning the thickness of the wall may be different at differentpoints along the wall.

The inside wall of the outer cap 1650-1 a has a bead 1601 that extendsaround the perimeter of the outer cap 1650-1 a, as seen in FIG. 16.Preferably the bead 1601 has a semi-circular cross section. However, thebead 1601 may have any other shaped cross section for example arectangular or oval cross section. These examples of bead 1601 crosssections are to be treated as examples only and are not limiting in anyway as many variations will suggest themselves to a person skilled inthe art on reading this specification. In the preferred form the crosssectional shape of the bead 1601 is constant along the entire perimeterof the outer cap 1650-1 a. Alternatively the shape of the bead 1601cross section may vary along different parts of the bead 1601 and theperimeter of the outer cap 1650-1 a—for example one section of bead mayhave a circular cross section while another part of the same bead mayhave a rectangular cross section.

The bead 1601 is preferably located near the top of the outer cap 1650-1a on the inner surface of the outer cap 1650-1, and in the preferredform of this embodiment running in an unbroken ring around the insidesurface of the outer cap 1650-1. More preferably the bead 1601 islocated between the top and two thirds along the outer cap height 1650-1a. Alternatively the bead may be placed anywhere along the inside wallof the outer cap 1650-1 a. As a further alternative the bead may vary inlocation as it extends or runs around the perimeter of the outer cap1650-1 a—for example the bead 1601 may be located half way up along theheight of the inside wall of the outer cap 1650-1 a at one point alongthe perimeter, while at another point along the perimeter the bead maybe located at the top of the inside wall of the outer cap 1650-1 a andso on. The placement of the bead may vary randomly or the bead may beplaced at specific weak points along the inside wall of the outer cap1650-1 a.

The thickness of the bead 1601 may be constant along the entireperimeter of the outer cap 1650-1 a. Preferably the thickness of thebead 1601 from its innermost point where it is joined to the surface ofthe outer cap to its outermost point is approximately twice the wallthickness of the outer cap 1650-1 a. However, the thickness of the beadmay be any thickness required for the particular type of patient andload conditions of the cap 1650-1. In a further alternative form thethickness of the bead 1601 may vary along the perimeter of the outer cap1650-1 a. Preferably the bead 1601 follows a symmetrical path around theouter cap 1650-1 a, as shown in FIG. 16. Alternatively the bead mayfollow any varying path along the inside wall of the outer cap 1650-1 a,as outlined above.

Surprisingly it has been found that the addition of the bead 1601 to theinside wall of the outer cap 1650-1 a helps to strengthen and stiffenthe section and surrounding sections of the outer cap 1650-1 along whichthe bead 1601 is placed. In the most preferred form the bead is placedaround the inside surface of the outer cap 1650-1, close to the top edgeof the inside wall of the outer cap 1650-1 a. The bead helps tostrengthen the particular area of the outer cap 1650-1 a that the bead1601 is placed at. The addition of the bead 1601 can stop or at leastreduce the amount the outer cap 1650-1 a collapses while being fittedinto a patient's nostril. The added stiffness of the outer cap 1650-1 a,due to the bead 1601, allows for a more effective seal to form betweenthe outer cap and the patient's nostril. Surprisingly it has also beenfound that the location of the bead 1601 in the most preferred form, asshown in FIG. 16, allows the upper part of the outer cap 1650-1 a tohold its shape while maintaining the flexibility of the lower part ofthe outer cap 1650-1 a. This allows the outer cap 1650-1 a to conform toa variety of nostril shapes and sizes.

The bead is purposely located out of the airway 1640 so that the bead isnot in the path of the gases delivered to the user. The bead 1601 isplaced out of the airway 1640 in order to minimise the pressure dropacross the pillows portion 1600 and reduce the effort required for userto exhale or breath through the pillows portion 1600. This provides theadvantage of making the use of the pillows portion 1600 more comfortablefor a user.

Surprisingly it has been found that a tapered inner cap 1650-1 b wallthickness helps to strengthen the inner cap 1650-1 b and stiffen theinner cap 1650-1 a. This is advantageous since in some circumstances inuse the inner cap 1650-1 b supports the outer cap 1650-1 a as it flexesand bends while fitting the caps into a patient's nose. This allows fora more effective seal being formed with the user's nostril. This alsostops the cap 1650-1 from collapsing into the airway 1640, stopping thedelivery of gases and making the pillows portion 1600 uncomfortable fora user to wear.

Surprisingly it has been found that the bead 1601 acts as a pivot pointfor the outer cap 1650-1 a when the outer cap 1650-1 a is depressedagainst the inner cap 1650-1 b during fitting of the outer cap 1650-1 ainto a user's nostrils. As the outer cap is being fitted into a user'snostrils the outer cap 1650-1 a flexes, bends and is depressed, bearingonto the inner cap 1650-1 b. The bead 1601 acts as a pivot point bybearing onto the inner cap 1650-1 b and allowing the top portion of theouter cap 1650-1 a to bend away from the airway 1640. This provides theadvantage of maintaining an open airway 1640 as the outer cap 1650-1 ais being fitted into a patient's nose. This is advantageous because itcontinuously allows the user to be supplied with therapy gases andprovides a comfortable seal for the user.

A further embodiment of a pillow portion 1700 is shown in FIG. 17. A cap1750-1 forms part of the pillow portion 1700. A pair of the pillowportions 1700 are preferably used with the pillow gasket 350-2 (notshown). The pillow portion 1700 is similar to pillow portion 800, withspecific structural differences as outlined below. As outlined above inthe specification, the pillows portion 1700 could be used with pillowgasket portion 250-2 or pillow gasket portion 450-2.

This embodiment has generally the same or similar elements to the firstgeneral form of the pillow portion (as described above). The specificvariations associated with this embodiment are described below.

In the most preferred form of this embodiment the cross sectionalthickness of the wall of the inner cap 1750-1 b is uniform along theheight of the inner cap 1750-1 b, as seen in FIG. 17. In a lesspreferred form the thickness of the wall of the inner cap 1750-1 b maytaper in any direction—meaning for example either the wall thickness atthe base 1705 may be greater than at the rim 1707 or vice versa. In thepreferred form the cross sectional thickness of the wall of the outercap 1750-1 a is uniform along the length of the outer cap 1750-1 a asseen in FIG. 17. Alternatively the cross sectional thickness of theouter cap 1750-1 a wall may vary along the height of the outer cap1750-1 a—meaning the thickness of the wall may be different at differentpoints along the wall.

The outer surface of the inner cap 1750-1 b includes a bead 1701. Thebead 1701 is preferably located at the rim 1707 and extends around theperimeter of the inner cap 1750-1 b. Preferably the bead 1701 has acircular cross section. Alternatively the bead may have any other shapedcross section, for example a rectangular cross section or triangular oroval cross section. The bead 1701 cross section shapes mentioned areonly examples and should not be construed as limiting in any way. Thebead 1701 is placed at the top or rim of the inner cap 1750-1 b, andmost preferably the bead extends around the rim 1707 of the inner cap1750-1 b. The bead 1701 extends symmetrically around the rim 1707 of theinner cap 1750-1 b. Alternatively the bead 1701 may be placed at varyinglocations along the top third of the inner cap 1750-1 b—that is, notjust at or around the rim 1707, but dipping lower down the outer surfaceof the inner cap 1750-1 b. The bead may also be discontinuous—that is,not a closed loop. As a further alternative the bead 1701 may be placedat specific weak points along the top part of the inner cap 1750-1 b. Inthis particular description ‘top part’ should be taken to refer to theupper sixth of the inner cap 1750-1 b.

Preferably the bead 1701 is thicker than the wall thickness of the innercap 1750-1 b. Even more preferably, the bead 1701 is twice the thicknessof the wall thickness of the inner cap 1750-1 b. In an alternative formthe bead 1701 may be thinner than the wall of the inner cap 1750-1 b.The thickness of the bead 1701 may be any thickness necessary for thespecific patient and loading conditions experienced by the inner cap1750-1 b. Preferably the thickness of the bead 1701 is uniform at allpoints along its perimeter. Alternatively the bead 1701 thickness mayvary from point to point along its perimeter. The variations inthickness may be deliberately created to strengthen certain weak pointsalong the top part of the inner cap 1750-1 b.

Surprisingly it has been found that adding the bead 1701 to the outersurface of the inner cap 1750-1 b helps to strengthen and add stiffness,particularly flexural stiffness, to the top part and rim 1707 of theinner cap 1750-1 b. Strengthening the top part of the inner cap 1750-1 bcan reduce the amount the inner cap or the top part of the inner capcollapses while fitting the pillows portion 1700 into a patient'snostrils. Strengthening the top part of the inner cap 1750-1 b helpskeep the airway 1740 open and doesn't force the patient to exert extraeffort to exhale through the cap 1750-1 and pillows portion 1700. Thisleads to added comfort for the patient and may help to enhance theeffectiveness of the therapy delivered to the patient.

Surprisingly the added strength of the inner cap 1750-1 b also providesmore support to the outer cap 1750-1 a. The outer cap 1750-1 can oftencollapse inwards toward the inner cap 1750-1 b while fitting the cap1750-1 and the nasal pillows portion into a patient's nostril. The outercap 1750-1 a collapsing can cause the inner cap 1750-1 b to deform orcollapse into the airway 1740, thus completely or partially blocking theflow of gases to a patient. This can increase the pressure drop acrossthe pillows portion 1700 and make it difficult for a patient to exhaleout of the pillows portion 1700. The blocking of the airway also reducesthe effectiveness of the therapy delivered to a patient. The bead 1701acts as a “bump stop” for the outer cap 1750-1 a. This means the outeredge of the bead 1701 acts as a support or limit for the outer cap1750-1 a as it is depressed. The outer edge of the bead 1701 will bearthe load of the outer cap 1750-1 a and can prevent the outer cap 1750-1a from collapsing into the airway 1740 and blocking the gases from beingdelivered to a patient. This limits the amount the outer cap 1750-1 awill collapse while being fitted into a patient's nostril. This providesthe advantage of making the pillows portion 1700 more comfortable to usesince there is not a large pressure drop across the pillow portion 1700and the patient does not have to exert too much effort to exhale.Further the gases delivery to the patient is not blocked and thus thetherapy delivered to the user is more effective. Limiting the depressionand flexing of the inner and outer caps also ensures a more effectiveseal is formed with a patient's nostrils and allows the pillows portion1700 and caps 1750-1 can be used with a variety of different shapednostrils.

A further embodiment of pillow portion 1800 is shown in FIG. 18. A pairof pillow portions 1800 are preferably used with the pillow gasket 350-2(not shown). The pillow portion 1800 is similar to pillow portion 800,with specific structural differences as described below. As outlinedabove in the specification, the pillows portion 1800 could be used withpillow gasket portion 250-2 or pillow gasket portion 450-2.

This embodiment has generally the same or similar elements as the firstgeneral form of the nasal pillow portion (described above). The specificvariations associated with this embodiment are described below.

In the most preferred form of this embodiment the cross sectionalthickness of the wall of the inner cap 1850-1 b is uniform along theheight of the inner cap 1850-1 b, as seen in FIG. 18. In a lesspreferred form the thickness of the wall of the inner cap 1850-1 b maytaper in any direction—meaning for example either the wall thickness atthe base 1805 may be greater than at the rim 1807 or vice versa. In thepreferred form the cross sectional thickness of the wall of the outercap 1850-1 a is uniform along the length of the outer cap 1850-1 a asseen in FIG. 18. Alternatively the cross sectional thickness of theouter cap 1850-1 a wall may vary along the height of the outer cap1850-1 a—meaning the thickness of the wall may be different at differentpoints along the wall.

The outer surface of the outer cap 1850-1 a includes a bead 1801 thatextends around the perimeter at the rim of the outer cap 1850-1 a.Preferably the bead 1801 is located around the rim of the outer cap1850-1 a. However, the bead 1801 may be located in the upper third ofthe outer surface of the outer cap 1850-1 a. In the most preferred formthe bead 1801 extends outwards from and around the rim 1806 of the outercap 1850-1 a, as seen in FIG. 18. Alternatively the bead 1801 may belocated at any point along the top third of the outside surface of theouter cap 1850-1 a and extend around the perimeter of the outer cap1850-1 a. As a further alternative, (not illustrated), the bead 1801 maybe placed at the top of the rim 1806, such that the centre point of thewall is located at the centre of the bead 1801—meaning the centre pointof the wall cross section is on the same vertical axis as the centrepoint of the bead cross section. Preferably the bead 1801 is thickerthan the cross sectional wall thickness of the outer cap 1850-1 a. Evenmore preferably the bead is twice the thickness of the cross sectionalwall thickness of the outer cap 1850-1 a. As an alternative the beadthickness may be thinner than the thickness of the wall of the outer cap1850-1 a, however, this form is not preferred. Preferably the thicknessof the bead is uniform along its perimeter. Alternatively the thicknessof the bead may vary along its perimeter, the thickness of the beadbeing different from point to point along its perimeter. The variationin thickness may be random due to manufacturing conditions or thevariation in thickness may be deliberate and the bead may be thicker orthinner at specific points along the perimeter of the outer cap 1850-1a.

The bead 1801 is most preferably circular in cross section. However, thebead 1801 may be any other cross section the manufacturer intends it tobe—for example the bead 1801 may have a rectangular cross section or anoval or triangular cross section. It should be noted that the crosssection shapes are only examples and should not be construed as limitingin any way, they are simply examples. The bead 1801 preferably follows asymmetrical path around the entire perimeter of the outer cap 1850-1 a.Alternatively the bead 1801 may follow any path along the outer cap1850-1 a perimeter—that is, not strictly following the upper rim, butdipping below this if required. Furthermore, the bead may be formeddiscontinuously around the perimeter or rim if required.

Surprisingly it has been found that the addition of the bead 1801 to theouter cap 1850-1 a helps to strengthen or add stiffness to the top partor the rim 1806 of the outer cap 1850-1 a. The added stiffness, inparticular flexural stiffness, to the top part or rim 1806 helps preventthe rim 1806 or to part of the outer cap 1850-1 a from collapsing andblocking the airway 1840 and restricting the flow of gases out of theairway 1840 and pillows portion 1800, while fitting the outer cap 1850-1a into a patient's nostrils. This provides the advantage of keeping theexit opening as big as possible while the outer cap 1850-1 a is beingfitted into a patient's nostrils. Preventing the airway 1840 from beingblocked reduces the amount of pressure drop across the pillows portion1800, and reduces the effort a patient has to exert in order to exhalethrough the cap 1850-1 and pillows portion 1800. This provides theadvantage of added comfort for the patient while using and fitting thepillows portion 1800.

The bead 1801 is purposely placed on the outer surface of the outer cap1850-1 a so that the bead is out of the path of the gases travellingthrough the airway 1840. This helps to reduce the amount of pressuredrop across the pillows portion 1800 and cap 1850-1. Reduced pressuredrop across the cap 1850-1 or pillows portion 1800 is advantageous as itmakes it easier for a patient to breath through the cap 1850-1 once itis inserted into a patient's nostril. This allows the patient to breathnormally and makes using the pillow portion 1800 and cap 1850-1 morecomfortable.

Surprisingly while the bead 1801 may strengthen or stiffen the top partor rim 1806 of the outer cap 1850-1 a, the lower part of the outer cap1850-1 a remains substantially flexible and supple. This flexibility andsuppleness allows the outer cap 1850-1 a to distort to fit into avariety of nostril shapes and form an effective seal. This allows thisparticular type of pillows portion 1800 and caps 1850-1 to be used witha variety of users to create an effective seal, while delivering therapygases.

A further embodiment of the pillow portion is shown as pillow portion1900 in FIG. 19. Pillow portion 1900 is preferably used as one of a pairwith the pillow gasket 350-2 (not shown). The pillow portion 1900 issimilar to pillow portion 800, with specific structural differences asoutlined below. As outlined above in the specification, the pillowsportion 1900 could be used with pillow gasket portion 250-2 or pillowgasket portion 450-2. In this embodiment the pillow section is formedfrom a pair of pillow portions and a pillow gasket portion.

This embodiment has generally the same or similar elements as the firstgeneral form of the nasal pillow portion (described above). Specificvariations associated with this embodiment are described below.

In the most preferred form of this embodiment the cross sectionalthickness of the wall of the inner cap 1950-1 b is uniform along theheight of the inner cap 1950-1 b, as seen in FIG. 19. In a lesspreferred form the thickness of the wall of the inner cap 1950-1 b maytaper in any direction—meaning for example either the wall thickness atthe base 1905 may be greater than at the rim 1907 or vice versa. In thepreferred form the cross sectional thickness of the wall of the outercap 1950-1 a is uniform along the length of the outer cap 1950-1 a asseen in FIG. 19. Alternatively the cross sectional thickness of theouter cap 1950-1 a wall may vary along the height of the outer cap1950-1 a—meaning the thickness of the wall may be different at differentpoints along the wall.

The outer wall of the inner cap 1950-1 b includes a bead 1901. The bead1901 extends around the perimeter of the inner cap 1950-1 b. The bead1901 may be located at any point vertically on the inner cap, except therim 1907. In the most preferred form the bead 1901 is locatedapproximately between the rim and two thirds of the way along the heightof the inner cap 1950-1 b, when measured from the base 1905 of the innercap 1950-1 b. However the bead 1901 may be located at any other pointalong the inner cap 1950-1 b.

The bead 1901 most preferably has a circular cross section.Alternatively the bead 1901 may have any other cross sectional shapethat can be manufactured—for example the bead may be rectangular incross section or oval in cross section. Preferably the cross section ofthe bead is constant along the entire perimeter of the inner cap 1950-1b. However, in some forms the cross section of the bead 1901 may changeshape at various points along the perimeter. Preferably the bead 1901 isthicker in cross section that the wall of the inner cap 1950-1 b, asseen in FIG. 19. Most preferably the bead 1901 is between approximatelyone third to two times the thickness of the wall thickness of the innercap 1950-1 b. Preferably the thickness of the bead is constant along theperimeter of the inner cap 1950-1 b. In an alternative form thethickness of the bead 1901 may vary from point to point along theperimeter of the inner cap 1950-1 b. This variation may be deliberate inorder to perhaps strengthen wear points along the inner cap or thisvariation in thickness may be caused due to other factors, for examplemanufacturing equipment faults.

Surprisingly it has been found the addition of the bead 1901 to theouter wall of the inner cap 1950-1 b may strengthen or add stiffness tothe upper section of the inner cap 1950-1 b. The bead helps to addstiffness against bending and deforming, in particular flexuralstiffness. The possible added strength and stiffness helps to reduce thetendency of the inner cap 1950-1 b to collapse into the airway 1940while fitting the cap 1950-1 or pillows portion 1900 into a patient'snostrils. During the fitting process the inner cap 1950-1 b may oftendeform and bend to fit into a patient's nostril to create an effectiveseal. This bending and the forces acting on the inner cap 1950-1 b causeit to collapse into the airway 1940, thus blocking or at least partiallyblocking the airway 1940. The addition of the bead helps to reduce orstop the inner cap from collapsing into the airway 1940 thus notrestricting the delivery of gases to a patient. Blocking the airway 1940can lead to increased pressure drop across the cap 1950-1 and leads toincreased effort by the patient to breathe through the cap 1950-1 andpillows portion 1900. Reducing or preventing the inner cap 1950-1 b fromcollapsing and blocking the airway ensures the patient can breathenormally through the cap 1950-1 or pillows portion 1900, making the capand pillows portion 1900 more comfortable to use.

Surprisingly it has been found the addition of bead 1901 to the innercap 1950-1 b also provides support to the outer cap 1950-1 a and helpsto reduce or prevent the outer cap 1950-1 a from collapsing. The outercap 1950-1 a deforms and bends more than the inner cap 1950-1 b whilefitting the pillows portion 1900 and cap 1950-1 into a patient'snostrils. As the outer cap 1950-1 a deforms and bends it usually bearsonto the inner cap 1950-1 b thus causing the inner cap 1950-1 b to bendor collapse into the airway 1940. The outer cap and inner cap bending orcollapsing into the airway 1940 can block or partially block the airway1940 and the flow of gases out of the airway. 1940. This can lead to anincreased pressure drop across the cap 1950-1 and increased breathingeffort by the patient to breathe through the cap 1950-1. The bead 1901acts as a travel limit “stop” or support for the outer cap 1950-1 a asit flexes and bears onto the inner cap 1950-1 b. The bead 1901 supportsthe weight of the bent or collapsed outer cap 1950-1 a and stops orreduces the deformation or collapse of the inner cap 1950-1 b due to thestiffness the bead 1901 adds to the inner cap 1950-1 b. The bead 1901limits the amount the inner cap 1950-1 b flexes, bends or collapses. Thebead 1901 also limits the amount the outer cap 19501-1 a bends orcollapses and limits the load the outer cap 1950-1 a places on the innercap 1950-1 b when the outer cap 1950-1 a is in its flexed or bent orcollapsed state. This provides the advantage of keeping the airway 1940open, reducing the pressure drop across the cap 1950-1 or pillowsportion 1900 and reducing the amount of breathing effort for thepatient, allowing the patient to breathe normally. The bead 1901 alsocontributes to allowing the cap 1950-1 to form a more effective seal byreducing the amount the inner and outer caps deform.

A further embodiment of the pillow portion 2000 is shown in FIG. 20. Apair of the pillow portions 2000 are preferably used with the pillowgasket 350-2 (not shown). The pillow portion 2000 is similar to pillowportion 800 with specific structural differences as described below. Asoutlined above in the specification, the pillows portion 2000 could beused with pillow gasket portion 250-2 or pillow gasket portion 450-2.

This embodiment has generally the same or similar elements as of thefirst general form of the pillow portion (described above). The specificvariations associated with this embodiment are described below.

In the most preferred form of this embodiment the cross sectionalthickness of the wall of the inner cap 2050-1 b is uniform along theheight of the inner cap 2050-1 b, as seen in FIG. 20. In a lesspreferred form the thickness of the wall of the inner cap 2050-1 b maytaper in any direction—meaning for example either the wall thickness atthe base 2005 may be greater than at the rim 2007 or vice versa. In thepreferred form the cross sectional thickness of the wall of the outercap 2050-1 a is uniform along the length of the outer cap 2050-1 a asseen in FIG. 20. Alternatively the cross sectional thickness of theouter cap 2050-1 a wall may vary along the height of the outer cap2050-1 a—meaning the thickness of the wall may be different at differentpoints along the wall.

The inner wall of the inner cap 2050-1 b includes a bead 2001 located onthe inner wall of the inner cap 2050-1 b. The bead is preferably locatedat and extends inwardly around the rim 2007 of the inner cap 2050-1 b.Alternatively the bead 2001 may be located at any point along the heightof the inner cap 2050-1 b on the inside wall, meaning the bead may belocated anywhere between the base 2005 and the rim 2007 of the inner cap2050-1 b. The bead 2001 still extends around the perimeter of the innercap 2050-1 b. Preferably the bead 2001 is symmetrical around theperimeter of the inner cap 2050-1 b, meaning in cross section the beadis a mirror image about a vertical axis in the centre of the cap 2050-1and stalk 2050-3, as seen in FIG. 20. In alternative arrangements thebead may follow any asymmetrical path around the perimeter of the innercap 2050-1 a.

FIG. 20 shows the preferred form of the bead 2001, in which the bead2001 has a substantially circular cross section. Alternatively the bead2001 may have any other cross section shape, for example a rectangularor oval cross section. The cross section shapes identified are onlyexamples and should not be construed as limiting, since on reading theabove description, a number of different possible cross-sections wouldsuggest themselves to a person skilled in the art. Preferably the bead2001 is thicker in cross sectional thickness than the cross sectionalthickness of the wall of the inner cap 2050-1 b, as best seen in FIG.20. Even more preferably the bead 2001 is twice as thick as the wall ofthe inner cap 2050-1 b. Alternatively the thickness of the bead may bethinner than the thickness of the wall of the inner cap 2050-1 b.Preferably the thickness of the bead 2001 is uniform along the entireperimeter of the inner cap 2050-1 b. Alternatively the bead thicknessmay vary from point to point along the perimeter of the inner cap 2050-1b. As a further alternative the bead 2001 may be thicker at one end ofthe rim and thinner at the other end.

It has surprisingly been found that the addition of the bead 2001 to theinside wall of the inner cap 2050-1 b adds strength and increasedstiffness to the upper section of the inner cap 2050-1 b, in particularthe rim 2001 and the surrounding area of the rim 2007. The additionalstiffness due to the bead 2001 helps to stop or reduce the amount theinner cap 2050-1 b collapses into the airway 2040, while fitting the cap2050-1 into a patient's nostrils. The inner cap 2050-1 b flexes whilefitting the cap 2050-1 into a patient's nostrils. The load on the innercap 20050-1 b may cause the inner cap 2050-1 b to partially orcompletely collapse or bend and block the airway 2040. Blocking theairway restricts the amount of gases being delivered to a patient,increases the pressure drop across the cap 2050-1 and increases thedifficulty of breathing through the cap 2050-1 for the user. The bead2001 assists in reducing or stopping the inner cap 2050-1 b fromcollapsing into the airway 2040. Hence sufficient amount of therapygases are delivered to the patient, there is less of a pressure dropacross the cap 2050-1 and the difficulty of breathing through the cap2050-1 and pillows portion 2000 is reduced. This leads to added comfortfor the patient and effective therapy for the patient.

A further embodiment of the pillow portion 2100 is shown in FIG. 21. Apair of the pillow portions are used with the pillow gasket 350-2 (notshown). The pillow portion 2100 is similar to pillow portion 800, withspecific structural differences as outlined below. As outlined above inthe specification, the pillows portion 2100 could be used with pillowgasket portion 250-2 or pillow gasket portion 450-2. In this embodimentthe pillow section is formed from a pair of the pillows portions and apillow gasket portion.

This embodiment has generally the same or similar elements as the firstgeneral form of the pillow portion (described above). The specificvariations associated with this embodiment are identified below.

In the most preferred form of this embodiment the cross sectionalthickness of the wall of the outer cap 2150-1 a is uniform along theheight of the outer cap 2150-1 a, as seen in FIG. 21. In a lesspreferred form the thickness of the wall of the outer cap 2150-1 a maytaper in any direction—meaning for example either the wall thickness atthe base 2104 may be greater than at the rim 2106 or vice versa. In thepreferred form the thickness of the wall of the inner cap 2050-1 b isuniform along the length of the inner cap 2050-1 b, as seen in FIG. 21.Alternatively the cross sectional thickness of the inner cap 2150-1 bwall may vary along the height of the inner cap 2150-1 b—meaning thethickness of the wall may be different at different points along thewall.

The outer cap 2150-1 a includes a bead 2101 located on the inner wall ofthe outer cap 2150-1 a. The bead is preferably located at and extendsaround the rim 2106 of the outer cap 2150-1 a. Alternatively the bead2101 may be located at any point along the height of the outer cap2150-1 a on the inside wall, meaning the bead may be located anywherebetween the base 2104 and the rim 2106 of the outer cap 2150-1 a. Thebead 2101 still extends around the perimeter of the outer cap 2150-1 a.Preferably the bead 2101 is symmetrical around the perimeter of theouter cap 2150-1 a, meaning in cross section the bead is a mirror imageabout a vertical axis in the centre of the cap 2150-1 and stalk 2150-3,as seen in FIG. 21. In alternative arrangements the bead may follow anasymmetrical path around the perimeter of the inner cap 2150-1 a.

FIG. 21 shows the preferred form of the bead 2101, in which the bead2101 has a substantially circular cross section. Alternatively the bead2101 may have any other cross section shape, for example a rectangularor oval cross section. The cross section shapes identified are onlyexamples and should not be construed as limiting, since many shapes forthe bead 2101 would suggest themselves to a person skilled in the artonce they have read the description above. Preferably the bead 2101 isthicker in cross sectional thickness than the cross sectional thicknessof the wall of the outer cap 2150-1 a, as best seen in FIG. 21. Evenmore preferably the bead 2101 is twice as thick as the wall of the outercap 2150-1 a. Alternatively the thickness of the bead may be thinnerthan the thickness of the wall of the outer cap 2150-1 a. Preferably thethickness of the bead 2101 is uniform along the entire perimeter of theouter cap 2150-1 a. Alternatively the bead thickness may vary from pointto point along the perimeter of the outer cap 2150-1 a. As a furtheralternative the bead 2101 may be thicker at one end of the rim andthinner at the other end.

It has surprisingly been found that the addition of the bead 2101 to theinside wall of the outer cap 2150-1 a adds strength and increasedstiffness to the upper section of the outer cap 2150-1 a, in particularthe rim 2101 and the surrounding area of the rim 2107. The additionalstiffness due to the bead 2101 helps to stop or reduce the amount theouter cap 2150-1 a collapses into the airway 2140, while fitting the cap2150-1 into a patient's nostrils. The outer cap 2150-1 a flexes duringfitting of the cap 2150-1 into a patient's nostrils. The load on theouter cap 2150-1 a from the patient's nostril causes the outer cap2150-1 a to partially or completely collapse or bend and block theairway 2140. Blocking the airway restricts the amount of gases beingdelivered to a patient, increases the pressure drop across the cap2150-1 and increases the difficulty of breathing through the cap 2150-1for the user. The bead 2101 helps to reduce or stop the outer cap 2150-1a from collapsing into the airway 2140. Hence sufficient amount oftherapy gases are delivered to the patient, there is less of a pressuredrop across the cap 2150-1 and reduces the difficulty of breathingthrough the cap 2150-1 and pillows portion 2100. This leads to addedcomfort for the patient and effective therapy for the patient.

An further embodiment of pillow portion 2200 is shown in FIG. 22. Thecap 2250-1 is part of a pillow portion 2200 (not shown) that ispreferably used with the pillow gasket 350-2 (not shown). The pillowportion 2200 is similar to pillow portion 800. As outlined above in thespecification, the pillows portion 2200 could be used with pillow gasketportion 250-2 or pillow gasket portion 450-2. In this embodiment thepillow section is formed from the pillows portion and pillow gasketportion.

This embodiment has generally the same or similar elements as the firstgeneral form of the pillow portion (described above). The specificvariations associated with this embodiment are described below. Thisembodiment is similar to the sixteenth embodiment with a few minordifferences that are identified below.

In the most preferred form the cross sectional thickness of the wall ofthe inner cap 2250-1 b tapers along the height of the inner cap 2250-1b, as seen in FIG. 22. The wall of the inner cap is preferably thickerat the base 2205 than at the rim 2207 of the inner cap 2250-1 b.However, the wall of the inner cap 2250-1 b may be thicker at the rim2207 than at the base 2205. In a less preferred form the thickness ofthe wall of the inner cap 2250-1 b may be uniform along the height ofthe inner cap 2250-1 b. In the preferred form the cross sectionalthickness of the wall of the outer cap 2250-1 a is uniform along thelength of the outer cap 2250-1 a as seen in FIG. 22. Alternatively thecross sectional thickness of the outer cap 2250-1 a wall may vary alongthe height of the outer cap 2250-1 a—meaning the thickness of the wallmay be different at different points along the wall.

The inner wall of the inner cap 2250-1 b includes a bead 2201 located onthe inner wall of the inner cap 2250-1 b. The bead is preferably locatedat and extends around the rim 2207 of the inner cap 2250-1 b.Alternatively the bead 2201 may be located at any point along the heightof the inner cap 2250-1 b on the inside wall, meaning the bead may belocated anywhere between the base 2205 and the rim 2207 of the inner cap2250-1 b. The bead 2201 still extends around the perimeter of the innercap 2250-1 b. Preferably the bead 2201 follows a symmetrical path aroundthe perimeter of the inner cap 2250-1 b, meaning in cross section thebead is a mirror image about a vertical axis in the centre of the cap2250-1 and stalk 2250-3, as seen in FIG. 22. In alternative arrangementsthe bead may follow any asymmetrical path around the perimeter of theinner cap 2250-1 a.

FIG. 22 shows the preferred form of the bead 2201, in which the bead2201 has a substantially circular cross section. Alternatively the bead2201 may have any other cross section shape, for example a rectangularor oval cross section. The cross section shapes identified are onlyexamples and should not be construed as limiting, since a number ofdifferent alternatives would suggest themselves to a person skilled inthe art on reading the above description. Preferably the bead 2201 isthicker in cross sectional thickness than the cross sectional thicknessof the wall of the inner cap 2250-1 b, as best seen in FIG. 22. Evenmore preferably the bead 2201 is twice as thick as the wall of the innercap 2250-1 b. Alternatively the thickness of the bead may be thinnerthan the thickness of the wall of the inner cap 2250-1 b. Preferably thethickness of the bead 2201 is uniform along the entire perimeter of theinner cap 2250-1 b. Alternatively the bead thickness may vary from pointto point along the perimeter of the inner cap 2250-1 b. As a furtheralternative the bead 2201 may be thicker at one end of the rim andthinner at the other end.

It has surprisingly been found that the addition of the bead 2201 to theinside wall of the inner cap 2250-1 b may add strength and increasedstiffness to the upper section of the inner cap 2250-1 b, in particularthe rim 2201 and the surrounding area of the rim 2207. The additionalstiffness due to the bead 2201 may stop or reduce the amount the innercap 2250-1 b collapses into the airway 2240, while fitting the cap2250-1 into a patient's nostrils. The inner cap 2250-1 b flexes duringwhile fitting the cap 2250-1 into a patient's nostrils. The load on theinner cap 22050-1 b may cause the inner cap 2250-1 b to partially orcompletely collapse or bend and block the airway 2240. Blocking theairway restricts the amount of gases being delivered to a patient,increases the pressure drop across the cap 2250-1 and increases thedifficulty of breathing through the cap 2250-1 for the user. The bead2201 can reduce or stop the inner cap 2250-1 b from collapsing into theairway 2240. Hence sufficient amount of therapy gases are delivered tothe patient, there is less of a pressure drop across the cap 2250-1 andreduces the difficulty of breathing through the cap 2250-1 and pillowsportion 2200. This leads to added comfort for the patient and effectivetherapy for the patient.

A further embodiment of pillow portion 2300 is shown in FIG. 23. The cap2350-1 is part of a pillow portion 2300 (not shown) that is preferablyused with the pillow gasket 350-2 (not shown). The pillow portion 2300is similar to pillow portion 800. As outlined above in thespecification, the pillows portion 2300 could be used with pillow gasketportion 250-2 or pillow gasket portion 450-2. In this embodiment thepillow section is formed from the pillows portion and pillow gasketportion.

This embodiment has generally the same or similar elements as the firstgeneral form of the pillow portion (as described earlier). The specificvariations associated with this embodiment are described below. Thepillow portions of the nineteenth embodiment are substantially similarto those described in the seventeenth embodiment. The general structureand differences are described below.

In the most preferred form the cross sectional thickness of the wall ofthe outer cap 2350-1 a is uniform along the height of the outer cap2350-1 a, as seen in FIG. 23. In a less preferred form the thickness ofthe wall of the outer cap 2350-1 a may taper in any direction—meaningfor example either the wall thickness at the base 2304 may be greaterthan at the rim 2306 or vice versa. In the preferred form the thicknessof the wall of the inner cap 2050-1 b tapers along the length of theinner cap 2050-1 b, as seen in FIG. 23. Preferably the inner cap 2350-1b wall is thicker at the base 2305 than at the rim 2307. However, thethickness of the wall of the inner cap 2350-1 b may be thicker at therim 2307 than at the base 2305, and the wall tapers in thickness.

The outer cap 2350-1 a includes a bead 2301 located on the inner wall ofthe outer cap 2350-1 a. The bead is preferably located at and extendsaround the rim 2306 of the outer cap 2350-1 a. Alternatively the bead2301 may be located at any point along the height of the outer cap2350-1 a on the inside wall, meaning the bead may be located anywherebetween the base 2304 and the rim 2306 of the outer cap 2350-1 a. Thebead 2301 still extends around the perimeter of the outer cap 2350-1 a.Preferably the bead 2301 follows a symmetrical path around the perimeterof the outer cap 2350-1 a, meaning in cross section the bead is a mirrorimage about a vertical axis in the centre of the cap 2350-1 and stalk2350-3, as seen in FIG. 23. In alternative arrangements the bead mayfollow any asymmetrical path around the perimeter of the inner cap2350-1 a.

FIG. 23 shows the preferred form of the bead 2301, in which the bead2301 has a substantially circular cross section. Alternatively the bead2301 may have any other cross section shape, for example a rectangularor oval cross section. The cross section shapes identified are onlyexamples and should not be construed as limiting, since many differentshapes of bead would suggest themselves to a person skilled in the artonce they have read the description above. Preferably the bead 2301 isthicker in cross sectional thickness than the cross sectional thicknessof the wall of the outer cap 2350-1 a, as best seen in FIG. 23. Evenmore preferably the bead 2301 is twice as thick as the wall of the outercap 2350-1 a. Alternatively the thickness of the bead may be thinnerthan the thickness of the wall of the outer cap 2350-1 a. Preferably thethickness of the bead 2301 is uniform along the entire perimeter of theouter cap 2350-1 a. Alternatively the bead thickness may vary from pointto point along the perimeter of the outer cap 2350-1 a. As a furtheralternative the bead 2301 may be thicker at one end of the rim andthinner at the other end.

It has surprisingly been found that the addition of the bead 2301 to theinside wall of the outer cap 2350-1 a may add strength and increasedstiffness to the upper section of the outer cap 2350-1 a, in particularthe rim 2301 and the surrounding area of the rim 2307. The additionalstiffness due to the bead 2301 may stop or reduce the amount the outercap 2350-1 a collapses into the airway 2340, while fitting the cap2350-1 into a patient's nostrils. The outer cap 2350-1 a flexes duringfitting of the cap 2350-1 into a patient's nostrils. The load on theouter cap 2350-1 a from the patient's nostril may cause the outer cap2350-1 a to partially or completely collapse or bend and block theairway 2340. Blocking the airway restricts the amount of gases beingdelivered to a patient, increases the pressure drop across the cap2350-1 and increases the difficulty of breathing through the cap 2350-1for the user. The bead 2301 can reduce or stop the outer cap 2350-1 afrom collapsing into the airway 2340. Hence sufficient amount of therapygases are delivered to the patient, there is less of a pressure dropacross the cap 2350-1 and reduces the difficulty of breathing throughthe cap 2350-1 and pillows portion 2300. This leads to added comfort forthe patient and effective therapy for the patient.

A further embodiment of pillow portion 2400 is shown in FIG. 24. The cap2450-1 is part of the pillow portion 2400 that is preferably used withthe pillow gasket 350-2 (not shown). The pillow portion 2400 is similarto pillow portion 800. As outlined above in the specification, thepillows portion 2400 could be used with pillow gasket portion 250-2 orpillow gasket portion 450-2. In this embodiment the pillow section isformed from the pillows portion and pillow gasket portion.

This embodiment has generally the same or similar elements as the firstgeneral form of the pillow portion (as described earlier). The specificvariations associated with this embodiment of the pillow portion aredescribed below.

In the most preferred form the cross sectional thickness of the wall ofthe outer cap 2450-1 a is uniform along the height of the outer cap2450-1 a, as seen in FIG. 24. In a less preferred form the thickness ofthe wall of the outer cap 2450-1 a may taper in any direction—meaningfor example either the wall thickness at the base 2404 may be greaterthan at the rim 2406 or vice versa. In the preferred form the thicknessof the wall of the inner cap 2050-1 b tapers along the length of theinner cap 2050-1 b, as seen in FIG. 24. Preferably the inner cap 2450-1b wall is thicker at the base 2405 than at the rim 2407. However, thethickness of the wall of the inner cap 2450-1 b may be thicker at therim 2407 than at the base 2405, and the wall tapers in thickness.Preferably the wall of the outer cap 2450-1 a is thinner than the wallof the inner cap 2450-1 b. Preferably the inner cap rim 2407 and outercap rim 2406 are the same height as each other.

It has surprisingly been found that the inner cap 2450-1 b and outer cap2450-1 a rims being the same height may make it easier for a patient oruser to breathe through the pillows portion 2400 and cap 2450-1. Theouter cap 2450-1 a rim 2406 extends to the same height as the inner cap2450-1 b rim 2407. It has been found that if the inner cap 2450-1 b andouter cap 2450-1 a are of the same vertical height, the outer cap 2450-1a collapses and rests against the inner cap 2450-1 b as the patient oruser exhales. The outer cap 2450-1 a collapsing and depressing againstthe inner cap 2450-1 b causes the inner cap 2450-1 b rim 2407 toprotrude out above the rim 2406 of the outer cap 2450-1 a. The rim 2407of the inner cap 2450-1 b protruding above the rim 2406 of the outer capeliminates any other alternate pathways for the air to travel out ofwhen a user is exhaling. The exhaled air is exhaled solely from airway2440 since the rim 2407 of the inner cap 2450-1 b protrudes above therim of the outer cap. This reduces the effort a user has to exert whilebreathing through and using the pillows portion 2400, thus making thepillows portion 2400 more comfortable and safer to use.

A further embodiment of pillow portion 2500 is shown in FIG. 25. The cap2550-1 is part of the pillow portion 2500 that is preferably used withthe pillow gasket 350-2 (not shown). The pillow portion 2500 is similarto pillow portion 800. As outlined above in the specification, thepillows portion 2500 could be used with pillow gasket portion 250-2 orpillow gasket portion 450-2. In this embodiment the pillow section isformed from the pillows portion and pillow gasket portion.

This embodiment has generally the same or similar elements as of thesecond general form of the nasal pillow portion (described earlier). Thespecific details of this embodiment are described below.

As can be seen in FIG. 25, the outer cap 2550-1 a and the air deliverytube 2560 are generally arranged with a common central axis. As can alsobe seen in FIG. 25, the outer cap 2550-1 a and air delivery tube 2560are of equal height. The rim 2506 of the outer cap 2550-1 a and the rim2507 of the air delivery tube 2560 are preferably in line and lie on thesame horizontal axis. However, the upper rims 2506 and 2507 aregenerally vertically aligned if the cap is fully upright. Preferably thepillow portions 2500 will be angled inwards towards each other on thegasket portion, similar to that as shown in FIGS. 11a and 11b . Theupper rims are not vertically aligned as the pillow portions 2500 areangled inwards towards each other.

In the preferred form the cap 2550-1 is wider at the base than the stalk2550-3. The outer cap 2550-1 a and air delivery tube 2560 merge at theirbases, with the base extending outwards almost perpendicular to the axisof the stalk 2550-3 before angling upwards and inwards. The shape of theouter cap and the air delivery tube 2560 allows the cap 2550-1 a or theair delivery tube 2560 or both to form a substantial seal with thenostril of the user, when in use. The walls of the outer 2550-1 a capare curved to help the cap to conform to a user's nostril and may assistin guiding a stream of gases from the pillow portions to the nostrils ofa user. The outer cap may curve or flare upwards such that in use theflare of the cap allows the cap 2550-1 a to form a substantial seal withthe nostril of the user, when in use. Preferably the walls of the outer2550-1 a cap are curved along a parabolic arc. The outer cap flaresupwards and outward in a similar manner as has already been describedfor the embodiments shown in FIGS. 7, 8, 14 and 15.

In the most preferred form the cross sectional thickness of the wall ofthe outer cap 2550-1 a is uniform along the height of the outer cap2550-1 a, as seen in FIG. 25. In a less preferred form the thickness ofthe wall of the outer cap 2550-1 a may taper in any direction—meaningfor example either the wall thickness at the base 2504 may be greaterthan at the rim 2506 or vice versa. Preferably the wall of the outer cap2550-1 a is thinner in cross sectional thickness than the wall of theair delivery tube 2560, as seen in FIG. 25. Preferably the air deliverytube 2560 tapers in thickness, meaning the thickness of the wall of theair delivery tube 2560 tapers, but that the inner sides or walls areparallel. Preferably the wall of the air delivery tube 2560 is thickerat its base 2505 than at its rim 2507. Alternatively the thickness ofthe wall of the air delivery tube 2560 may be thicker at the rim andthinner at its base. In a further alternative form the wall of the airdelivery tube 2560 may be of uniform thickness along its height.

Surprisingly it has been found adding an air delivery tube 2560 withinternal straight-sides into the cap 2550-1 better directs airflow topatient's nostril, aides in sealing against the nostrils of a patientand reduces the breathing effort required by the patient to breathethrough the pillows portion 2500 (not shown). The flexibility of theouter cap 2550-1 a allows the outer cap to bend and deform to fit anyshaped nostril. This allows the pillows portion to be used with avariety of nostril shapes. The thinner and more flexible outer cap alsoflexes such that the stiffer air delivery tube is positionedsubstantially in the centre of a patient's nostrils when in use. The airdelivery tube 2560 being in the centre of a patient's nostrils betterdirects air flow and gases into a patient's nostrils. The air deliverytube 2560 being rigid helps the outer cap 2550-1 a to form a better sealwith the patient's nostrils, because the air delivery tube 2560 does notdeform and acts as a support for the outer cap 2550-1 a.

Surprisingly it has been found that air delivery tube directs air into apatient's nostrils with a minimal pressure drop across the pillowsportion 2500 and the cap 2550-1. This reduced pressure drop makes iteasier for a user to breathe through the cap 2550-1 since there is alower resistance to the air flowing through the air delivery tube.Further there is less resistance to the air flowing through the airdelivery tube 2560 because the air delivery tube does not collapse ordeform when in use. This means the airway 2540 (the path of the gases orair) is unhindered and obstacle free, thus reducing the pressure dropacross the pillows portion 2500 and the cap 2550-1. The reduced pressuredrop makes it easier for a patient to breathe through the pillowsportion 2500 and cap 2550-1 when in use, leading to more effectivetherapy and added comfort for the user.

Surprisingly it has been found that the addition of the air deliverytube 2560 to the cap 2550-1 reduces the effort a patient has to apply toexhale and breathe through the pillows portion and the cap 2550-1. Acommon problem that may occur is exhaled air being trapped within thecap or exhaled air flowing into various gaps within the cap—for examplethe exhaled air commonly flows into the gap 2510 between the outer cap2550-1 a and the air delivery tube 2560. The air becomes trapped therewhen the outer cap 2550-1 a is in use. The stiff air delivery tube 2560offers a support for the outer cap 2550-1 a to lean against as the outercap depresses when in use. The outer cap 2550-1 a leans against the airdelivery tube 2550-1 a causing the rim 2507 of the air delivery tube2560 to protrude above the rim of the outer cap, thus sealing off thegap 2510. This restricts the exhaled air to flow out of the air deliverytube 2560 only, reducing the effort the user has to apply to breathethrough the pillows portion 2500 and the cap 2550-1 since the exhaledair has a clear unhindered pathway to exit.

A further embodiment of pillow portion 2600 is shown in FIG. 26. The cap2650-1 is part of a pillow portion 2600 that is preferably used with thepillow gasket 350-2 (not shown). The pillow portion 2600 is similar topillow portion 800. As outlined above in the specification, the pillowsportion 2600 could be used with pillow gasket portion 250-2 or pillowgasket portion 450-2. In this embodiment the pillow section is formedfrom the pillows portion and pillow gasket portion.

This embodiment has generally the same or similar elements as the firstgeneral form of the pillow portion (described earlier). The specificvariations associated with this embodiment are described below.

In the preferred form of this embodiment the walls of the inner cap2650-1 b taper in cross sectional thickness as best seen in FIG. 26. Thewalls of the inner cap 2650-1 b are thicker at the base 2605 of theinner cap 2650-1 b than at the rim 2607 of the inner cap 2650-1 b. Inthe preferred form the cross sectional thickness of the inner cap 2650-1b wall may be thicker than the cross sectional thickness of the outercap 2650-1 a wall. This means the thinnest part of the inner cap 2650-1b wall may be thicker than the outer cap 2650-1 a wall. Alternativelythe wall of the inner cap 2650-1 b may be uniform in thickness.Preferably the wall of the outer cap 2650-1 a is tapered in thickness.The wall of the outer cap 2650-1 a is thicker at the rim 2606 of theouter cap 2650-1 a than at the base 2604 of the outer cap 2650-1 a, asseen in FIG. 26, with a sharp edge, as seen in FIG. 26. Alternativelythe edge of the rim 2606 may be slightly rounded to make it easier tomanufacture.

Surprisingly it has been found that having a larger cross sectional wallthickness at the rim 2606 of the outer cap 2650-1 a improves thestrength and stiffness of the outer cap 2650-1 a and the rim 2606section of the outer cap 2650-1 a. A common problem that occurs when thepillow portion 2600 is in use is that the outer cap 2650-1 a isdepressed by the user's nostrils. The outer cap 2650-1 a may collapse ordeform and possibly block the path of the gases being delivered to thepatient through the pillow portion 2600. The thicker rim 2606 of theouter cap 2650-1 b may prevent the rim 2606 from collapsing when the rim2606 is depressed by the patient's nostrils as the rim 2606 is insertedinto a patient's nostrils. Preventing the outer cap 2650-1 a fromcollapsing and blocking the gases from exiting the pillow portion 2600may prevent an increase in the pressure drop across the pillow andprevents the patient from exerting excessive effort to exhale throughthe pillow portion 2600. This particular advantage leads to moreeffective therapy, added comfort and safety for the patient.

It has also surprisingly been found that a thicker wall section at therim 2606 of the outer cap 2650-1 a assists in maintaining the airway2640 open, which can partially collapse when the user or patient isexhaling. The thicker wall section adds strength and stiffness to theouter cap 2650-1 a, in particular the rim section 2606 of the outer cap2650-1 a and may stop the rim section or the outer cap 2650-1 a fromcollapsing. It has also surprisingly been found that the thicker rim2606 section may result in the outer cap 2650-1 a being substantiallyflexible and supple allowing the pillow portion 2600 to form aneffective seal with the user's nostril.

A further embodiment of pillow portion 2700 is shown in FIG. 27. The cap2750-1 is part of a pillow portion 2700 that is preferably used with thepillow gasket 350-2 (not shown). The pillow portion 2700 is similar topillow portion 800. As outlined above in the specification, the pillowsportion 2700 could be used with pillow gasket portion 250-2 or pillowgasket portion 450-2. In this embodiment the pillow section is formedfrom the pillows portion and pillow gasket portion.

This embodiment has generally the same or similar elements as the secondgeneral form of the pillow portion (described above). The specificvariations are described below.

As can be seen in FIG. 27, the outer cap 2750-1 a and the air deliverytube 2760 are generally arranged with a common central axis. As can alsobe seen in FIG. 27, the air delivery tube 2760 extends upward furtherthan the outer cap 2750-1 a. The rim 2706 of the outer cap 2750-1 a islower than the rim 2707 of the air delivery tube 2760, meaning the airdelivery tube 2760 extends above the rim of the outer cap 2750-1 a asseen in FIG. 27.

The outer cap 2750-1 a and air delivery tube 2760 merge at their bases,with the base extending outwards almost perpendicular to the axis of thestalk 2750-3 before angling upwards and inwards. The shape of the outercap and the air delivery tube 2760 allows the cap 2750-1 a or the airdelivery tube 2760 or both to form a substantial seal with the nostrilof the user, when in use. The walls of the outer 2750-1 a cap are curvedupwards and outwards. Preferably the air delivery tube 2760 extendsbeyond the upper rim of the outer cap and guides a stream of gases fromthe pillow portions to the nostrils of a user. The outer cap 2750-1 aacts as a cushion for the nostril to sit on when the air delivery tube2760 is inserted into a patient's nostril. The air delivery tube 2760may be sized such that it can form a seal with the patient's nostrils.Preferably the walls of the outer 2750-1 a cap are curved along aparabolic arc.

In the most preferred form the cross sectional thickness of the wall ofthe outer cap 2750-1 a is uniform along the height of the outer cap2750-1 a, as seen in FIG. 27. In a less preferred form the thickness ofthe wall of the outer cap 2750-1 a may taper in any direction—meaningfor example either the wall thickness at the base 2704 may be greaterthan at the rim 2706 or vice versa. Preferably the wall of the outer cap2750-1 a is thinner in cross sectional thickness than the wall of theair delivery tube 2760, as seen in FIG. 27. Preferably the air deliverytube 2760 tapers in thickness, meaning the thickness of the wall of theair delivery tube 2760 tapers, but that the internal sides or walls aresubstantially straight or parallel. Preferably the wall of the airdelivery tube 2760 is thicker at its base 2705 than at its rim 2707.Alternatively the thickness of the wall of the air delivery tube 2760may be thicker at the rim and thinner at its base. In a furtheralternative form the wall of the air delivery tube 2760 may be ofuniform thickness along its height.

Surprisingly it has been found that adding the air delivery tube 2760into the cap 2750-1 better directs airflow to patient's nostril, aidesin sealing against the nostrils of a patient and reduces the breathingeffort required by the patient to breathe through the pillows portion2700 (not shown). The flexibility of the outer cap 2750-1 a allows theouter cap to bend and deform to fit any shaped nostril. This allows thepillows portion to be used with a variety of nostril shapes. The thinnerand more flexible outer cap also flexes such that the stiffer airdelivery tube is positioned substantially in the centre of a patient'snostrils when in use. The air delivery tube 2760 being in the centre ofa patient's nostrils better directs air flow and gases into a patient'snostrils and may also avoid the air delivery tube 2760 from contactingthe soft tissue within a patient's nostrils. The air delivery tube 2760being stiffer than the outer cap 2750-1 a helps the outer cap 2750-1 ato form a better seal with the patient's nostrils, because the airdelivery tube 2760 does not deform and acts as a support for the outercap 2750-1 a. The flexibility of the outer cap 2750-1 a also allows theouter cap to flex and act as a cushion to support the nostrils of apatient.

Surprisingly it has been found that air delivery tube directs air into apatient's nostrils with a minimal pressure drop across the pillowsportion 2700 and the cap 2750-1. This reduced pressure drop makes iteasier for a user to breathe through the cap 2750-1 since there is alower resistance to the air flowing through the air delivery tube.Further there is less resistance to the air flowing through the airdelivery tube 2760 because the air delivery tube does not collapse ordeform when in use. This means the airway 2740 (the path of the gases orair) is unhindered and obstacle free, thus reducing the pressure dropacross the pillows portion 2700 and the cap 2750-1. The reduced pressuredrop makes it easier for a patient to breathe through the pillowsportion 2700 and cap 2750-1 when in use, leading to more effectivetherapy and added comfort for the user.

Surprisingly it has been found that the addition of the air deliverytube 2760 to the cap 2750-1 reduces the effort a patient has to apply toexhale and breathe through the pillows portion and the cap 2750-1. Acommon problem that may occur is exhaled air being trapped within thecap or exhaled air flowing into various gaps within the cap—for examplethe exhaled air commonly flows into the gap 2710 between the outer cap2750-1 a and the air delivery tube 2760. The air becomes trapped thereas the outer cap 2750-1 a is in use. The air delivery tube 2760 extendsabove the rim of the outer cap 2750-1 a and so an exhaled air from thepatient is exhaled through the air delivery tube only, reducing theeffort required to breath through the cap 2760-1. Further since theouter cap 2750-1 a is also flexible and acts as a cushion, the gap 2710is sealed due the outer cap 2750-1 a bending while in use and supportinga patient's nostrils. This restricts the exhaled air to flow out of theair delivery tube 2760 only, reducing the effort the user has apply tobreathe through the pillows portion 2700 and the cap 2750-1 since theexhaled air has a clear unhindered pathway to exit.

A further embodiment of pillow portion 2800 is shown in FIG. 28. The cap2850-1 is part of a pillow portion 2800 that is preferably used with thepillow gasket 350-2 (not shown). The pillow portion 2800 is similar topillow portion 800. As outlined above in the specification, the pillowsportion 2800 could be used with pillow gasket portion 250-2 or pillowgasket portion 450-2. In this embodiment the pillow section is formedfrom the pillows portion and pillow gasket portion.

This embodiment has generally the same or similar elements as the firstgeneral form of the nasal pillow portion (described earlier). Thisembodiment is substantially similar to the embodiment described above inreference to FIG. 24. Both this embodiment and the twentieth embodimenthave the same structural features, except in this embodiment the innercap rim 2807 extends further vertically than the outer cap rim 2806 whenthe pillow portion is not in use.

It has surprisingly been found that the inner cap 2850-1 b rim extendingfurther upward than the outer cap 2850-1 a rim may make it easier for apatient or user to breathe through the pillows portion 2800 (not shown)and cap 2850-1. The inner cap 2850-1 b rim 2807 extending higher thanthe outer cap 2850-1 a rim 2806 limits the exhaled air to flow paths. Acommon problem that can occur is that the exhaled air flows out of theairway 2840 or may flow into the gap 2810 between the outer and innercap, shown in FIG. 28. This can make breathing difficult for the patientor user since the patient or user has to exert more effort to push anyexhaled air trapped in the cap 2850-1, for example air trapped in thegap 2810. This may also make the pillows portion 2800 possibly unsafe touse since it could damage the patient's lungs or diaphragm because thepatient has to exert a lot of effort to breathe through the pillowsportion 2800. The exhaled air being trapped in the cap 2850-1 or gap2810 is further compounded by the outer cap 2850-1 a collapsing anddepressing against the inner cap 2850-1 b as the patient exhales. Theouter cap 2850-1 a collapses because the wall of the outer cap 2850-1 ais thinner than the inner cap 2850-1 b and cannot support as much loadas the wall of the inner cap 2850-1 b. Therefore the outer cap 2850-1 bcollapses and the inner cap 2850-1 b remains upright, as the patientexhales. It has been found that if the inner cap 2850-1 b extendsfurther than the outer cap 2850-1 a eliminates any other alternatepathways for the air to travel out of. The exhaled air is exhaled out ofairway 2840 since the rim 2807 of the inner cap 2850-1 b protrudes abovethe rim of the outer cap. This reduces the effort a user has to exertwhile breathing through and using the pillows portion 2800, thus makingthe pillows portion 2800 more comfortable and safer to use.

A further embodiment of pillow portion 2900 is shown in FIG. 29. The cap2950-1 is part of a pillow portion 2900 that is preferably used with thepillow gasket 350-2 (not shown). The pillow portion 2900 is similar topillow portion 800. As outlined above in the specification, the pillowsportion 2900 could be used with pillow gasket portion 250-2 or pillowgasket portion 450-2. In this embodiment the pillow section is formedfrom the pillows portion and pillow gasket portion.

This embodiment has generally the same or similar elements as the secondgeneral form of the pillow portion (described earlier). The specificvariations associated with this embodiment are described below.

As can be seen in FIG. 29, the air delivery tube 2960 and the outer cap2950-1 a are generally arranged concentrically with a common centralaxis. As can also be seen in FIG. 29, the outer cap 2950-1 a extendsfurther upwards than the air delivery tube 2960. The rim 2906 of theouter cap 2950-1 a extends above the rim 2907 of the air delivery tube2960. Preferably the pillow portions 2900 will be angled inwards towardseach other on the gasket portion, similar to that as shown in FIGS. 11aand 11b . The upper rims are not vertically aligned as the pillowportions 2900 are angled inwards towards each other.

In the most preferred form the cross sectional thickness of the wall ofthe outer cap 2950-1 a is uniform along the height of the outer cap2950-1 a, as seen in FIG. 29. In a less preferred form the thickness ofthe wall of the outer cap 2950-1 a may taper in any direction—meaningfor example either the wall thickness at the base 2904 may be greaterthan at the rim 2906 or vice versa. In the preferred form the thicknessof the wall of the air delivery tube tapers along its height. The airdelivery tube 2960 is thicker at its base 2906 than at its rim 2907 orvice versa. The thickness of the delivery tube 2960 may vary from pointto point along the height of the delivery tube 2960. Alternatively thecross sectional thickness of the wall of the air delivery tube 2960 maybe uniform.

The outer cap 2950-1 a includes a bead 2901 located on the inner wall ofthe outer cap 2950-1 a, as seen in FIG. 29. The bead is preferablylocated at and extends around the rim 2906 of the outer cap 2950-1 a.Alternatively the bead 2901 may be located at any point along the heightof the outer cap 2950-1 a on the inside wall, meaning the bead may belocated anywhere between the base 2904 and the rim 2906 of the outer cap2950-1 a. The bead 2901 still extends around the perimeter of the outercap 2950-1 a. Preferably the bead 2901 follows a symmetrical around theperimeter of the outer cap 2950-1 a, meaning in cross section the beadis a mirror image about a vertical axis in the centre of the cap 2950-1and stalk 2950-3, as seen in FIG. 29. In alternative arrangements thebead may follow any asymmetrical path around the perimeter of the innercap 2950-1 a.

FIG. 29 shows the preferred form of the bead 2901, in which the bead2901 has a substantially circular cross section. Alternatively the bead2901 may have any other cross section shape, for example a rectangularor oval cross section. The cross section shapes identified are onlyexamples and should not be construed as limiting, since any shape forthe bead 2901 cross section would be obvious to a person skilled in theart. Preferably the bead 2901 is thicker in cross sectional thicknessthan the cross sectional thickness of the wall of the outer cap 2950-1a, as best seen in FIG. 29. Even more preferably the bead 2901 is twiceas thick as the wall of the outer cap 2950-1 a. Alternatively thethickness of the bead may be thinner than the thickness of the wall ofthe outer cap 2950-1 a. Preferably the thickness of the bead 2901 isuniform along the entire perimeter of the outer cap 2950-1 a.Alternatively the bead thickness may vary from point to point along theperimeter of the outer cap 2950-1 a. As a further alternative the bead2901 may be thicker at one end of the rim and thinner at the other end.

It has surprisingly been found that the addition of the bead 2901 to theinside wall of the outer cap 2950-1 a may add strength and increasedstiffness to the upper section of the outer cap 2950-1 a, in particularthe rim 2901 and the surrounding area of the rim 2907. The additionalstiffness due to the bead 2901 may stop or reduce the amount the outercap 2950-1 a collapses into the airway 2940, while fitting the cap2950-1 into a patient's nostrils. The outer cap 2950-1 a flexes duringwhile fitting the cap 2950-1 into a patient's nostrils. The load on theouter cap 2950-1 a from the nostril may cause the outer cap 2950-1 a topartially or completely collapse or bend and block the airway 2940.Blocking the airway restricts the amount of gases being delivered to apatient, increases the pressure drop across the cap 2950-1 and increasesthe difficulty of breathing through the cap 2950-1 for the user. Thebead 2901 can reduce or stop the outer cap 2950-1 a from collapsing intothe airway 2940. Hence sufficient amount of therapy gases are deliveredto the patient, there is less of a pressure drop across the cap 2950-1and reduces the difficulty of breathing through the cap 2950-1 andpillows portion 2900. This leads to added comfort for the patient andeffective therapy for the patient. Furthermore since the air deliverytube 2960 is rigid, the air delivery tube 2960 acts as a support and mayhold up the outer cap 2950-1 a as the outer cap collapses or flexeshelping to keep the airway 2940 unblocked or at least partiallyunblocked. This can lead to reduced pressure drop across the pillowportion 2900, leading to reduced breathing effort and comfort for thepatient.

Surprisingly it has been found that adding an air delivery tube 2960with straight substantially parallel walls into the cap 2950-1 helps tobetter direct airflow into a patient's nostril and reduces the breathingeffort required by the patient to breathe through the pillows portion2900. The outer cap 2950-1 a is preferably more flexible and supple thanthe air delivery tube 2960. The flexibility of the outer cap 2950-1 aallows it to bend and form to fit any shaped nostril. This allows thepillows portion 2900 and cap 2950-1 to be used with a wide variety ofnostril shapes. Preferably the outer cap 2950-1 a is also thinner thanthe air delivery tube 2960. The thinner outer cap 2950-1 a flexes whenengaged with a patient's nostrils such that the air delivery tube ispositioned substantially in the centre of the patient's nostrils. Theair delivery tube positioned in the middle of a patient's nostrils helpsto better direct airflow and gases into the patient's nostrils. The airdelivery tube in the centre of the patient's nostrils also may stop theair delivery tube 2960 from contacting the soft tissue inside thepatient's nostrils making the cap 2950-1 more comfortable and safer touse.

Surprisingly it has been found that the air delivery tube delivers airor gases to a patient's nostrils with minimal pressure drop across thecap 2950-1 and pillows portion 2900. This reduced pressure drop makes iteasier for a user to breathe through the cap 2950-1 since there is alower resistance to the air flowing through the air delivery tube 2960.Further there is less resistance to the air flowing through the airdelivery tube 2960 because the air delivery tube is substantially stiffand does not collapse or deform when engaged with a patient's nostrils.The airway 2940 (the path of the gases or air) is unhindered, thusreducing the pressure drop across the pillows portion 2900 and the cap2950-1. The reduced pressure drop makes it easier for a patient tobreathe through the pillows portion 2900 and cap 2950-1 since thepatient does not need to exert extra effort to breathe, leading tosafer, more comfortable and more effective therapy.

A further embodiment of pillow portion 3000 is shown in FIG. 30. The cap3050-1 is part of a pillow portion 3000 that is preferably used with thepillow gasket 350-2 (not shown). The pillow portion 3000 is similar topillow portion 800. As outlined above in the specification, the pillowsportion 3000 could be used with pillow gasket portion 250-2 or pillowgasket portion 450-2. In this embodiment the pillow section is formedfrom the pillows portion and pillow gasket portion.

This embodiment has generally the same or similar elements as the secondgeneral form of the pillow portion (described earlier). The specificvariations associated with this embodiment are described below.

As can be seen in FIG. 30, the air delivery tube 3060 and the outer cap3050-1 a are generally arranged concentrically with a common centralaxis. The air delivery tube has a generally straight and parallel-sidedinternal wall. As can also be seen in FIG. 30, the outer cap 3050-1 aextends further upwards than the air delivery tube 3060. The rim 3006 ofthe outer cap 3050-1 a extends above the rim 3007 of the air deliverytube 3060. Preferably the pillow portions 3000 will be angled inwardstowards each other on the gasket portion, similar to that as shown inFIGS. 11a and 11b . The upper rims are not vertically aligned as thepillow portions 3000 are angled inwards towards each other.

In the most preferred form the cross sectional thickness of the wall ofthe outer cap 3050-1 a tapers along the height of the outer cap 3050-1a, as seen in FIG. 30. Preferably the wall of the outer cap 3050-1 a isthicker at its base 3004 than at its rim 3006, as seen in FIG. 30.Alternatively the wall of the outer cap 3050-1 a may be thicker at therim 3006 and thinner at the base 3004. In the preferred form thethickness of the wall of the air delivery tube 3060 tapers along itsheight. The air delivery tube 3060 is thicker at its base 3006 than atits rim 3007, as seen in FIG. 30, or vice versa. The thickness of thedelivery tube 3060 may also vary from point to point along the height ofthe delivery tube 3060. Alternatively the cross sectional thickness ofthe wall of the air delivery tube 3060 may be uniform.

Surprisingly it has been found that adding the air delivery tube 3060into the cap 3050-1 helps to better direct airflow into a patient'snostril and reduces the breathing effort required by the patient tobreathe through the pillows portion 3000. The outer cap 3050-1 a ispreferably more flexible and supple than the air delivery tube 3060. Theflexibility of the outer cap 3050-1 a allows it to bend and form to fitany shaped nostril. This allows the pillows portion 3000 and cap 3050-1to be used with a wide variety of nostril shapes. Preferably the outercap 3050-1 a is also thinner than the air delivery tube 3060. Thethinner outer cap 3050-1 a flexes when engaged with a patient's nostrilssuch that the air delivery tube is positioned substantially in thecentre of the patient's nostrils. The air delivery tube positioned inthe middle of a patient's nostrils helps to better direct airflow andgases into the patient's nostrils. The air delivery tube in the centreof the patient's nostrils also stops the air delivery tube 3060 fromcontacting the soft tissue inside the patient's nostrils making the cap3050-1 more comfortable and safer to use.

Surprisingly it has been found that the air delivery tube delivers airor gases to a patient's nostrils with minimal pressure drop across thecap 3050-1 and pillows portion 3000. This reduced pressure drop makes iteasier for a user to breathe through the cap 3050-1 since there is alower resistance to the air flowing through the air delivery tube 3060.Further there is less resistance to the air flowing through the airdelivery tube 3060 because the air delivery tube is stiffer than thethin-walled outer cap and does not collapse or deform when engaged witha patient's nostrils. The airway 3040 (the path of the gases or air) isunhindered, thus reducing the pressure drop across the pillows portion3000 and the cap 3050-1. The reduced pressure drop makes it easier for apatient to breathe through the pillows portion 3000 and cap 3050-1 sincethe patient does not need to exert extra effort to breathe, leading tosafer, more comfortable and more effective therapy.

It has also surprisingly been found that tapering the thickness of thewall of the outer cap 3050-1 a helps to strengthen and add stiffness tothe outer cap 3050-1 a. The stiffness helps the outer cap 3050-1 a tomaintain its shape when it is in use and engaged with patient'snostrils. The added stiffness helps to stop the amount the outer cap3050-1 a deforms and reduces the amount the outer cap 3050-1 a collapsesunder the load from the patient's nostril. The tapered wall thicknessalso helps to maintain the flexibility of the upper part of the outercap 3050-1 a. The increased flexibility allows the outer cap 3050-1 a tobe used with a wide variety of nostril shapes. Reduced deformation andthe flexibility of the outer cap 3050-1 a helps the outer cap 3050-1 ato form an effective seal with a patient's nostrils. The added stiffnesscan also help to reduce the pressure drop across the pillows portion3000 and cap 3050-1 since the outer cap does not collapse and block theairway 3040. This leads to added comfort and more effective therapy to apatient.

A further embodiment of pillow portion 3100 is shown in FIG. 31. The cap3150-1 is part of a pillow portion 3100 that is preferably used with thepillow gasket 350-2 (not shown). The pillow portion 3100 is similar topillow portion 800. As outlined above in the specification, the pillowsportion 3100 could be used with pillow gasket portion 250-2 or pillowgasket portion 450-2. In this embodiment the pillow section is formedfrom the pillows portion and pillow gasket portion.

This embodiment has generally the same or similar elements as the secondgeneral form of the pillow portion (described earlier). The specificvariations associated with this embodiment are described below. Thisembodiment is very similar in structure to the embodiment shown in FIG.30, except that the air delivery tube wall has a constant thickness.

As can be seen in FIG. 31, the air delivery tube 3160 and the outer cap3150-1 a are generally arranged concentrically with a common centralaxis. As can also be seen in FIG. 31, the outer cap 3150-1 a extendsfurther upwards than the air delivery tube 3160. The rim 3106 of theouter cap 3150-1 a extends above the rim 3107 of the air delivery tube3160. Preferably the pillow portions 3100 will be angled inwards towardseach other on the gasket portion, similar to that as shown in FIGS. 11aand 11b . The upper rims are not vertically aligned as the pillowportions 3100 are angled inwards towards each other.

In the most preferred form the cross sectional thickness of the wall ofthe outer cap 3150-1 a is thicker at its base 3104 than at its rim 3106.In the preferred form the thickness of the wall of the air delivery tube3160 tapers along its height, with the internal wall beingparallel-sided. The air delivery tube 3160 is thicker at its base 3106than at its rim 3107, as seen in FIG. 31, or vice versa. The thicknessof the delivery tube 3160 may also vary from point to point along theheight of the delivery tube 3160. Alternatively the cross sectionalthickness of the wall of the air delivery tube 3160 may be uniform. Inthe preferred form the thickness of the wall of the air delivery tube3160 is thicker than that of the outer cap 3150-1 a wall.

Surprisingly it has been found that adding the air delivery tube 3160into the cap 3150-1 helps to better direct airflow into a patient'snostril and reduces the breathing effort required by the patient tobreathe through the pillows portion 3100. The outer cap 3150-1 a ispreferably more flexible and supple than the air delivery tube 3160. Theflexibility of the outer cap 3150-1 a allows it to bend and form to fitany shaped nostril. This allows the pillows portion 3100 and cap 3150-1to be used with a wide variety of nostril shapes. Preferably the outercap 3150-1 a is also thinner than the air delivery tube 3160. Thethinner outer cap 3150-1 a flexes when engaged with a patient's nostrilssuch that the air delivery tube is positioned substantially in thecentre of the patient's nostrils. The air delivery tube positioned inthe middle of a patient's nostrils helps to better direct airflow andgases into the patient's nostrils. The air delivery tube in the centreof the patient's nostrils also may stop the air delivery tube 3160 fromcontacting the soft tissue inside the patient's nostrils making the cap3150-1 more comfortable and safer to use.

Surprisingly it has been found that the air delivery tube delivers airor gases to a patient's nostrils with minimal pressure drop across thecap 3150-1 and pillows portion 3100. This reduced pressure drop makes iteasier for a user to breathe through the cap 3150-1 since there is alower resistance to the air flowing through the air delivery tube 3160.Further there is less resistance to the air flowing through the airdelivery tube 3160 because the air delivery tube is substantially stiffand does not collapse or deform when engaged with a patient's nostrils.The airway 3140 (the path of the gases or air) is unhindered, thusreducing the pressure drop across the pillows portion 3100 and the cap3150-1. The reduced pressure drop makes it easier for a patient tobreathe through the pillows portion 3100 and cap 3150-1 since thepatient does not need to exert extra effort to breathe, leading to moreeffective therapy and makes the pillows portion 3150 more comfortableand safer to use.

A further embodiment of the pillows portion 3200 is shown in FIG. 32.FIG. 32 shows an alternate configuration of rib arrangement. Thisembodiment as described below could be applied to any one of the otherembodiments described herein. FIG. 32 shows four separate ribs 3201 thatare preferably evenly spaced (that is, at substantially equal intervals)around the pillow portion 3250-1, between the inner and the outer caps,or the outer cap and the inner air delivery tube. That is, each of theribs runs radially outwards and is spaced from the two ribs to each sideby substantially a ninety-degree angle.

Surprisingly it has been found that the addition of the ribs 3201 in theconfiguration shown in FIG. 32 may strategically add strength to theinner or outer caps without compromising the flexibility of the caps.The flexibility of the caps allows them to be fitted and used with avariety of nostril shapes. The added structural strength provided by theribs helps to reduce the deformation the caps undergo under the loadsfrom a user's nostrils. Further the orientation of the ribs may enhancethe characteristics and advantages described for each of the varioustypes of ribs in the embodiments shown in FIGS. 5-9.

A further embodiment of the pillows portion 3300 is shown in FIG. 33.FIG. 33 shows an alternate configuration of rib arrangement. Thisembodiment as described below could be applied to any one of the otherembodiments described herein. FIG. 33 shows two separate ribs 3301 thatare preferably placed at one end of the cap 3350-1, meaning the ribs areplaced in close vicinity to each other. The ribs 3301 are preferablyangled at between sixty and one hundred and twenty degrees relative toeach other. In the most preferred form the ribs are at ninety degrees toeach other. It is most preferred that one of the ribs points backwardsand slightly inwards (in use), with the other one of the ribs arrangedso that it points outwards to one side and slightly backwards.

Surprisingly it has been found that the addition of the ribs 3301 in theconfiguration shown in FIG. 33 may strategically add strength to theinner or outer caps without compromising the flexibility of the caps.The flexibility of the caps allows them to be fitted and used with avariety of nostril shapes. The added strength helps to reduce thedeformation the caps undergo under the loads from a user's nostrils.

In the embodiments shown in FIGS. 32 and 33, as described above, it ismost preferred that the ribs are thin and parallel-sided. The ribs arearranged running radially outwards. It should be noted that ‘radially’as used in this context should be taken to mean that the ribs arealigned so that they appear to run outwards from a centre point(although in these embodiments, the ribs do not extend to a central axisof the pillow portion).

A further embodiment of pillows portion 3400 is shown in FIG. 34.

FIG. 34 shows an alternate configuration of rib arrangement. Thisembodiment as described below could be applied to any one of the otherembodiments described herein. FIG. 34 shows two separate ribs 3401,which are located between the outer cap and the inner cap or the innerair delivery tube. Most preferably the two ribs are placed so that theyare aligned substantially vertically, and run outwards radially. In themost preferred form the ribs 3401 are at an angle of substantially onehundred and eighty degrees to each other. Alternatively the ribs 3401may be at angle between one hundred and sixty to two hundred degreesrelative to each other. The inner rib (that closest to the user) pointsslightly outwards and towards the user.

As described above, it is most preferred that the ribs are thin andparallel-sided. The ribs are arranged running radially outwards. Itshould be noted that ‘radially’ as used in this context should be takento mean that the ribs are aligned so that they appear to run outwardsfrom a centre point (although in these embodiments, the ribs do notextend to a central axis of the pillow portion)

Surprisingly it has been found that the addition of the ribs 3401 in theconfiguration shown in FIG. 34 may strategically add strength to theinner or outer caps without compromising the flexibility of the caps.The flexibility of the caps allows them to be fitted and used with avariety of nostril shapes. The added strength helps to reduce thedeformation the caps undergo under the loads from a user's nostrils.Further the orientation of the ribs may enhance the characteristics andadvantages described for each of the various types of ribs in theembodiments shown in FIGS. 5-9.

A still further embodiment of the pillows portion 3500 is shown in FIG.35.

This embodiment is substantially similar to the embodiments shown inFIGS. 32, 33 and 34, as described above, except that there are threeradial ribs arranged spaced at substantially equidistant angles aroundthe circumference of the pillow portion. In the most preferred form,there is one rib on the inner side of the pillow (closest to the user)and this faces slightly inwards. There is one rib on the side of thepillow section, and this faces outwards to the side and slightly towardsthe user. The third and final rib is aligned substantially at sixtydegree to the other tow ribs in the preferred from. However, it shouldbe noted that the three ribs could be rotated around to any point on thecircumference as appropriate.

A further embodiment of nasal pillow portion is shown in FIGS. 36a, 36band 36c . In this variation, the pillow portion is shown as being usedwith the pillow gasket portion 350-2 (although as outlined above, thesecould be used with pillow gasket portion 250-2 or pillow gasket portion450-2. In this embodiment, the pillow section is formed from the pillowportions and the pillow gasket portion.

This embodiment is made up of the first general form of the pillowportion (described earlier). The specific variations associated withthis variation are described below.

In the preferred form of this embodiment the walls of the inner cap3650-1 b and the outer cap 3650-1 a taper in cross sectional thicknessas best seen in FIG. 36c . The walls of the inner cap 3650-1 b and theouter 3650-1 a are thicker at the lower end. The wall of the outer cap3650-1 a is thicker at the base 3604 of the outer cap 3650-1 a than atthe rim 3606 of the outer cap 3650-1 a, and the wall of the inner cap3650-1 b is thicker at the base 3605 of the inner cap 3650-1 b than atthe rim 3607 of the inner cap 3650-1 b. Alternatively the thickness ofthe walls of the inner and outer cap may be constant or the wallthickness of one of the walls may taper while the wall thickness of theother wall may remain constant.

The inside surface of the wall of the outer cap 3650-1 b contains atleast one and preferably a pair of partial ribs 3601. In alternateembodiments, the inner or inside surface of the wall of the outer cap3650-1 a may contain three or more partial ribs 3601. If a series ofpartial ribs is used, the partial ribs 3601 can be positioned at regularor differing intervals around the perimeter of the inside surface of thewall of the outer cap 3650-1 a. The pair of partial ribs 3601 extendonly a partial length along the height of the inside wall of the outercap. Preferably the height of each of the partial ribs is less than theheight of the outer cap 3650-1 a. The partial ribs can have the sameheight as one another, or different heights. The partial ribs can alsohave different thicknesses, or the same thickness. The partial ribs aregreater in size than the beads described above, and in the particularembodiment described are located at the top rim, running downwards, ofthe outer cap. The partial ribs only run part of the height or length ofthe cap (hence ‘partial’).

Preferably each of the partial ribs is substantially circular in crosssection. However the partial rib may be any other cross sectional shape,for example a square or triangular cross section. The partial rib ispreferably placed along the rim 3606 of the outer cap. Most preferablythe upper end of the partial rib is at the rim 3606 of the outer cap3650-1 a, with the rest of the partial rib extending down along theinside surface of the outer cap 3650-1 a. Preferably the partial ribs3601 extend downwards up to three quarters of the way down along theinside surface of the outer cap 3650-1 a, but not all the way to thebottom or base of the cap sections. Most preferably the upper end of therib 3601 is at the rim 3606, and the rib extends downwards around onesixth of the height of the inside surface of the outer cap 3650-1 a whenmeasured from the rim 3606 of the outer cap 3650-1 a, as shown in FIG.36c . However, each one of the pair could be in different positionsalong the inside surface of the outer cap 3650-1 a.

It should particularly be noted that the ribs 3601 of this embodimentare rounded so that their ends blend into the inner surface of the outercap 3650-1 a—that is, they do not have ‘cornered’ or ‘sharp’ upper andlower edges or surfaces. The rib 3601 is thicker in the middle than itis at its extremes. The width of the ribs 3601 is preferably constant.(‘Width’ in this context is the side-side dimension of the rib 3601—thatis, the dimension into and out of the page in FIG. 36c . In thisembodiment, the width of the pair of ribs is constant).

It should be noted that in the preferred form shown in FIG. 36c , therib or ribs 3601 are located towards the top of the wall 3650-1 a, andnot towards the base. Further it should be noted that one edge of therib 3601 extends from the rim 3606 of the outer cap 3650-1 a.

Surprisingly, it has been found that a rib or ribs 3601 in this form actto increase the strength of the outer pillow wall 3650-1 a in certainareas to control and manipulate the collapse of the outer pillow wall3650-1 a when the cap 3650-1 is inserted into the nostril of a user. Bycontrolling the collapse, the pillow wall 3650-1 a will have moremovement in some areas rather than others. This is advantageous aspillows can be produced which are both more comfortable and which alsooffer good sealing properties against the nares of a user.

The addition of a pair of ribs 3601 spaced equidistant around theperimeter of the inner surface of the outer cap 3650-1 a helps toimprove the strength of the rim 3606 of the outer cap 3650-1 a in orderto minimise the collapse of the rim 3606 into the airway 3640. Theaddition of the rib 3601 adds stiffness and acts as to support the rim3606 of the outer cap 3650-1 a, to stop it collapsing under the load ofa patient's nostril. This keeps the airway 3640 unblocked and reducesthe pressure drop across the pillows portion 3600 and cap 3650-1. Thisreduced pressure drop makes it easier for a user to breathe through thepillows portion 3600 and cap 3650-1, making the cap and pillows portionmore comfortable and safer to use.

The addition of the rib 3601 also helps to improve the feel of positiveaffirmation of the pillow 3600 being correctly inserted into thenostril, from the user's point of view, to reduce the occurrence of thepillow 3600 being incorrectly fitted. The added stiffness of the rim3606, due to the rib 3601, can stop the rib from completely collapsingand allows the rim to hold its shape while fitting the cap 3650-1 into apatient's nostril. This added stiffness provides the user with anindication of a correct fit and also indicates to the user that the cap3650-1 has formed an effective seal with the user's nostril.

A further embodiment of nasal pillow section is shown in FIGS. 37a, 37b,and 37c . In this variation, the pillow portions are shown as being usedwith the pillow gasket portion 350-2, (but as outlined above, the pillowportions may be used with the pillow gasket portion 250-2 or pillowgasket portion 450-2). The specific variations associated with thisembodiment are described below.

This embodiment is generally made up of the first general form of thepillow portion (described earlier). The specific variations associatedwith this embodiment are described below.

In this embodiment the walls of the inner cap 3750-1 b and the outer cap3750-1 a taper in cross sectional thickness, as best seen in FIG. 37c .The wall of the inner cap 3750-1 b is preferably thicker at the base3705 of the inner cap 3750-1 b than at the rim 3707 of the inner cap3750-1 b. The wall of the outer cap 3750-1 a is preferably thicker atthe base of the 3704 of the outer cap 3750-1 a than at the rim 3706 ofthe outer cap 3750-1 a. Alternatively the wall thickness of the innercap 3750-1 b and the outer cap 3750-1 a may be uniform. As anotheralternative the wall thickness of the inner and outer caps may be equalto each other—meaning the wall of the inner cap 3750-1 b is the samethickness as the wall of the outer cap 3750-1 a. Further to this thewall cross section of the inner and outer cap may be identical to eachother. As a further alternative the thickness of the wall of one of thecaps may taper while the thickness of the other cap wall may beuniform—for example the thickness of the wall of the inner cap 3750-1 bmay taper while the thickness of the wall of the outer cap 3750-1 a maybe uniform.

There is a cavity 3710 or air gap formed between the outer cap 3750-1 aand the inner cap 3750-1 b (except at the point where they are connectedat their bases to the stalk 3750-3 and to each other). The cavity or airgap 3710 is not in the direct air path of the stream of gases, as bestseen in FIG. 37 c.

The cap 3750-1 includes at least one “rib” feature within the cap.Preferably this rib feature is a solid fin 3701 that passes through theentire cap 3750-1. The fin 3701 joins the inner cap 3750-1 b with theouter cap 3750-1 a, as seen if FIGS. 37a and 37b . Preferably part ofthe fin 3701 lies within the path of the stream of gases delivered tothe user or patient, as seen in FIG. 37a . The fin 3701 extends from theinside surface of the outer cap 3750-1 a to the outside surface of theinner cap 3750-1 b, as best seen in the left cap of FIG. 37b . The fin3701 preferably extends from the top edge of the outer cap 3750-1 a tothe top edge of the inner cap 3750-1 b. The fin 3701 extends from oneside of the cap to the other side of the cap, spanning the diameter ofthe cap 3750-1, as seen in FIG. 37 b, and from the top to the bottom ofthe cap. Preferably the fin 3701 follows the contours of the overall capshape. Preferably the fin 3701 extends vertically from the bottom of theouter surface of the inner cap 3750-1 b to the top of the outer cap3750-1 a. The fin is shown as straight in plan view as it passes fromone side of the cap to the other. Alternatively the fin 3701 could becurved in shape (not shown), instead of being straight as shown in FIGS.37a and 37b , and form a gentle curve, preferably an inverted parabolaas it passes through the entire cap 3750-1. As a further alternative thefin 3701 could be angled about the central vertical axis of the exitorifice 3720 of the cap 3750-1, or alternatively the fin 3701 may beoffset about the vertex point. The vertex point preferably is situatedin the middle of the exit orifice 3720 of the cap 3750-1. However, thevertex point may be at any point along the width of the cap 3750-1. As afurther alternative the fin 3701 may completely extend through the cap3750-1. In this alternative form the fin 3701 may only extend from theinner surface of the outer cap 3750-1 a to the point where the cap3750-1 extends from the stalk (this arrangement is not illustrated),similar to the sixth embodiment previously described.

The fin 3701 preferably tapers in thickness. The fin 3701 is thicker atits base than at the rim 3706 of the outer cap 3750-1 a, meaning the fin3701 is thicker where it attaches to the outer surface of the inner cap3750-1 b than at the point where it attaches to the inner surface of theouter cap 3750-1 a. Alternatively the fin 3701 may be thicker at the rim3706 of the outer cap 3750-1 a than at the base of the caps. As afurther alternative the fin 3701 may have uniform thickness along itsprofile. In the preferred form the cap 3750-1 only includes one fin 3701per cap 3750-1, but the each cap may include multiple fins 3701 spacedat varying or constant distances from one another. The fin is preferablyrigid and made from the same materials as the cap portion 3750-1.

Surprisingly it has been found that adding a fin 3701 to the cap 3750-1may result in strengthening the entire cap 3750-1 structure. Theaddition of the fin 3701 adds stiffness to the cap 3750-1 andstrengthens both the inner and outer caps. The fin may prevent the innerand outer caps from folding and permanently deforming. Since the cap3750-1 is stiffer and can resist permanent deformation, this providesthe advantage that the cap 3750-1 and hence the pillow portions 3700 canbe correctly fitted into a patient's nostrils and the cap 3750-1.

While strengthening the cap 3750-1 structure the addition of the fin3701 still allows the cap to maintain flexibility either side of the fin3701. This flexibility may allow the cap 3750-1 to elastically deform asthe cap conforms to the nostrils of the user and allows the cap toprovide a better seal with the nostrils of the user.

It has also surprisingly been found that the addition of the fin 3701may go some way to prevent the collapse of the outer cap 3750-1 a fromcollapsing into the path of the stream of gases and close the orifice3720 of the caps. The closing or partially closing of the orifice 3720increases pressure drop of across of the cap 3750-1 and increases theeffort needed by the user or patient to exhale through the nasalinterface. The addition of the fin 3701 may aide in preventing the outercap 3750-1 a from collapsing into the orifice 3720 and into the path ofthe stream gases, thus improving comfort and safety for the user. Thefin 3701 also provides the advantage of delivering more effectivetherapy since the addition of the fin 3701 provides a better seal andhelps in preventing the outer cap 3750-1 a from collapsing into the pathof the stream of gases and from sealing up the orifice 3720.

In the preferred form the fin 3701 cross sectional thickness is tapered.The fin 3701 is thicker at the base of the inner 3750-1 b and outer3750-1 a caps than at the rim 3706 of the outer cap 3750-1 a, asdescribed. This tapering thickness directs airflow from the stalks outof the orifice 3720 and out of the cap 3750-1. The addition of the finand the tapered cross section of the fin helps in reducing the velocityof the delivered gases to a velocity that is comfortable for a user toaccept the stream of gas. The possible reduction in velocity may alsohelp prevent air jetting effects that can annoy or damage the nasalpassages of a user. The fin 3701 helps to maintain a low level ofpressure drop across the nasal interface when the interface is in use.This again increases comfort for the user.

A further embodiment of the pillow portions is shown in FIGS. 38a, 38b ,and 38 c. In this variation, the pillow portions are shown as being usedwith the pillow gasket portion 350-2, (but as outlined above, the pillowportions may be used with the pillow gasket portion 250-2 or pillowgasket portion 450-2). The specific variations associated with thisembodiment are described below.

This embodiment is made up of the first general form of the pillowportion (described earlier). Specific variations associated with thisembodiment are described below.

In the preferred form of this embodiment the walls of the inner cap3850-1 b and the outer cap 3850-1 a taper in cross sectional thickness,as best seen in FIG. 38c . The wall of the inner cap 3850-1 b ispreferably thicker at the base 3805 of the inner cap 3850-1 b than atthe rim 3807 of the inner cap 3850-1 b. The wall of the outer cap 3850-1a is preferably thicker at the base of the 3804 of the outer cap 3850-1a than at the rim 3806 of the outer cap 3850-1 a. Alternatively the wallthickness of the inner cap 3850-1 b and the outer cap 3850-1 a may beuniform. As another alternative the wall thickness of the inner andouter caps may be equal to each other—meaning the wall of the inner cap3850-1 b is the same thickness as the wall of the outer cap 3850-1 a.Further to this the wall cross section of the inner and outer cap may beidentical to each other. As a further alternative the thickness of thewall of one of the caps may taper while the thickness of the other capwall may be uniform—for example the thickness of the wall of the innercap 3850-1 b may taper while the thickness of the wall of the outer cap3850-1 a may be uniform.

There is a cavity 3810 or air gap formed between the outer cap 3850-1 aand the inner cap 3850-1 b (except at the point where they are connectedat their bases to the stalk 3850-3 and to each other). The cavity or airgap 3810 is not in the direct air path of the stream of gases, as bestseen in FIG. 38 c.

The cap 3850-1 includes at least one “rib” feature within the cap.Preferably this rib feature is a solid fin 3801 that passes through theentire cap 3850-1. The fin 3801 joins the inner cap 3850-1 b with theouter cap 3850-1 a, as seen if FIGS. 38b and 38c . Preferably part ofthe fin 3801 lies within the path of the stream of gases delivered tothe user or patient, as seen in FIG. 38a . The fin 3801 extends from theinside surface of the outer cap 3850-1 a to the outside surface of theinner cap 3850-1 b, as best seen in the left cap of FIGS. 38b and 38c .The fin 3801 preferably extends across the width or diameter of theouter cap 3850-1 a, with the lower edge of the fin 3801 passing acrossand contacting (or formed with) the rim 3807 of the inner cap 3850-1 b.The fin 3801 only extends downwards as far as the rim 3807 of the innercap 3850-1 b. The fin 3801 extends from one side of the cap to the otherside of the cap, spanning the diameter of the cap 3850-1, as seen inFIG. 38 b. Preferably the fin 3801 extends vertically from rim of theinner cap 3850-1 b to the rim of outer cap 3850-1 a. The fin 3801follows the general shape of the top edges of the cap 3850-1.Alternatively the fin 3801 could be curved in shape (not shown), insteadof being straight as shown in FIGS. 38a and 38b , and form a gentlecurve along between the rim of the inner and outer caps. As a furtheralternative the fin 3801 could be even angled about the central verticalaxis of the exit orifice 3820 of the cap 3850-1, as seen in FIG. 38a oralternatively the fin 3801 may be offset about the vertex point. Thevertex point preferably is situated in the middle of the exit orifice3820 of the cap 3850-1. However, the vertex point may be at any pointalong the width of the cap 3850-1. As a further alternative the fin 3801may completely extend through the cap 3850-1. In this alternative formthe fin 3801 may only extend from the inner surface of the outer cap3850-1 a to the point where the cap 3850-1 extends from the stalk (thisarrangement is not illustrated), similar to the sixth embodimentpreviously described.

The fin 3801 preferably tapers in thickness. The fin 3801 is thicker atits base, along the rim of the inner cap 3850-1 b, than at the rim 3806of the outer cap 3850-1 a. Alternatively the fin 3801 may be thicker atthe rim 3806 of the outer cap 3850-1 a than at the rim 3807 of the innercap 3850-1 b. As a further alternative the fin 3801 may have uniformthickness along its profile. In the preferred form the cap 3850-1 onlyincludes one fin 3801 per cap 3850-1, but the each cap may includemultiple fins 3801 spaced at varying or constant distances from oneanother. The fin is preferably made from the same materials as the capportion 3850-1.

Surprisingly it has been found that adding a fin 3801 to the cap 3850-1may result in strengthening the entire cap 3850-1 structure. Theaddition of the fin 3801 adds stiffness to the cap 3850-1 andstrengthens both the inner and outer caps. The fin may prevent the innerand outer caps from folding and permanently deforming. Since the cap3850-1 is stiffer and can resist permanent deformation, this providesthe advantage that the cap 3850-1 and hence the pillow portions 3800 canbe correctly fitted into a patient's nostrils and the cap 3850-1.

While strengthening the cap 3850-1 structure the addition of the fin3801 still allows the cap to maintain flexibility either side of the fin3801. This flexibility may allow the cap 3850-1 to elastically deform asthe cap conforms to the nostrils of the user and allows the cap toprovide a better seal with the nostrils of the user and make it easierto fit into a patient or user's nostrils.

It has also surprisingly been found that the addition of the fin 3801may go some way to prevent the collapse of the outer cap 3850-1 a fromcollapsing into the path of the stream of gases and close the orifice3820 of the caps. The closing or partially closing of the orifice 3820increases pressure drop of across of the cap 3850-1 and increases theeffort needed by the user or patient to exhale through the nasalinterface. The addition of the fin 3801 may aide in preventing the outercap 3850-1 a from collapsing into the orifice 3820 and into the path ofthe stream gases, thus improving comfort and safety for the user. Thefin 3801 also provides the advantage of delivering more effectivetherapy since the addition of the fin 3801 provides a better seal andhelps in preventing the outer cap 3850-1 a from collapsing into the pathof the stream of gases and from sealing up the orifice 3820.

In the preferred form the fin 3801 cross sectional thickness is tapered.The fin 3801 is thicker at the base of the inner 3850-1 b and outer3850-1 a caps than at the rim 3806 of the outer cap 3850-1 a, asdescribed. This tapering thickness directs airflow from the stalks outof the orifice 3820 and out of the cap 3850-1. The addition of the finand the tapered cross section of the fin helps in reducing the velocityof the delivered gases to a velocity that is comfortable for a user toaccept the stream of gas. The possible reduction in velocity may alsohelp prevent air jetting effects that can annoy or damage the nasalpassages of a user. The fin 3801 helps to maintain a low level ofpressure drop across the nasal interface when the interface is in use.This again increases comfort for the user.

A further embodiment of the pillow portions is shown in FIGS. 39a, 39b ,and 39 c. In this variation, the pillow portions are shown as being usedwith the pillow gasket portion 250-2 (but as outlined above, the pillowportions may be used with the pillow gasket portion 350-2 or pillowgasket portion 450-2).

This embodiment is formed from the same elements as form the thirdgeneral form of the pillows portion (described above), with specificdifferences as described below.

In the preferred form of this embodiment the wall of the cap 3950-1tapers in thickness, being thicker at the base 3904 than at the rim3907. It is preferred that the wall thickness tapers gradually. Mostpreferably the wall thickness at the base 3904 of the cap 3950-1 istwice the thickness at the rim 3907 of the cap 3950-1. In alternativeforms the wall of the cap 3950-1 may be thicker at the rim 3907 andthinner at the base 3904. In further alternate forms the thickness ofthe wall of the cap 3950-1 may be uniform along the entire height of thecap 3950-1.

The inside surface of the cap 3950-1 includes at least one andpreferably a series of ribs 3901 which extend inward from the innersurface of the cap 3950-1. The rib or ribs 3901 preferably extend towardthe centre of the cap or inward toward each other. The ribs 3901 arepreferably located within the top third of the cap 3950-1. That is, theribs are situated between the top 3907 of the cap 3950-1 andapproximately one third of the way down the inside surface of the ribwhen measured from the top 3907. In the most preferred form, the top ofthe rib or ribs 3901 is located at the rim 3907 of the cap 3950-1. Theinner edge of the rib 3901 is attached to the inside surface of the cap3950-1 wall, while the outer edge is a free edge. Preferably the freeedge of the rib 3901 is substantially curved between the top and thebottom, as shown in FIG. 39c . Preferably the rib or ribs are thickercloser to the top of the rib. The rib tapers or curves and becomesthinner toward the bottom of the rib, merging with the pillow wall atthe bottom of the rib. It can be seen that the rib has a ‘teardrop’shape in cross-section.

In alternative forms the free edge the rib 3901 may have a cross-sectionin the shape of some other polygon, for example a triangle or rectangle.The rib 3901 is substantially elongate vertically. Preferably the edgeattached to the inner wall of the cap 3950-1 extends downward along theinner wall of the cap 3950-1, toward the stalk 3950-3. Most preferablythe rib extends down approximately one third of the total cap 3950-1height, along the inner wall of the cap 3950-1, when measured from therim 3907. Most preferably the rib extends downward from the rim 3907 ofthe cap 3950-1. Alternatively the rib 3901 may extend downward anywherebetween one eighth and two thirds of the total height of the cap 3950-1from the rim 3907. These rib/ribs 3901 can be called partial ribs sincein the preferred form the rib or ribs 3901 do not extend all the way tothe base of the cap 3950-1.

It is preferred that the rib 3901 has the same cross-sectional thicknessas the cross-sectional thickness of the cap 3950-1, at the thickestpoint along the height of the cap 3950-1. More preferably the rib isthicker than the cap 3950-1 at the thickest point of the cap (that is,the rib extends inwards further than the thickness of the cap). Inalternative, less preferred forms, the rib 3901 may be thinner than thecap 3950-1 wall thickness.

If a series of ribs 3901 are used, it is most preferred that they areall identical to each other. In the preferred form the ribs 3901 arepositioned at regular, evenly spaced intervals around the perimeter ofthe cap 3950-1. Alternatively the ribs 3901 may be placed at irregularintervals around the perimeter of the cap 3950-1. Preferably all theribs 3901 extend the same length downwards from the rim of the cap3950-1. Alternatively the various ribs 3901 may extend varying distancesalong the height of the cap 3950-1. These varying intervals and varyingextension along the height may be used to add strength (via the rib orribs) along specific weak points on the cap 3950-1. Preferably all theribs are placed along one axis around the perimeter of cap 3950-1,meaning all the ribs are at the same height around the perimeter of thecap 3950-1. Alternatively the ribs may be placed at various heightsaround the perimeter of the cap 3950-1. In the most preferred form theribs 3901 all have the same cross-sectional thickness. However, it isconceivable that the ribs may vary in cross-sectional thickness from ribto rib. In the most preferred form, the cap 3950-1 has two ribs 3901spaced at 180 degrees (radially opposite) from each other along theperimeter of the cap.

The addition of the rib(s) 3901, and more preferably a series of ribshelps to strengthen or stiffen the wall of the cap 3950-1. The addedstiffness, in particular added flexural stiffness, helps to reduce theamount of deformation of the cap 3950-1, when the cap is fitted into apatient's nostrils. The rib or ribs 3901 help to control the amount ofdeformation of those portions of the cap 3950-1 where the rib ispresent. The areas of the cap 3950-1 with the rib are stiffer and moveless than the areas of the cap 3950-1 without the rib 3901. Theadditional stiffening of certain areas of the cap 3950-1 can help toform a more effective seal with the patient's nostril. This allows thecap 3950-1 to be used and fitted to a variety of different shapednostrils. The addition of the rib or ribs 3901 makes the cap 3950-1 morecomfortable for the user to use.

The addition of the rib 3901 around the perimeter of the cap 3950-1helps to stiffen and strengthen the cap 3950-1 so that it does notcollapse onto itself and block the airway 3940. If the cap 3950-1 blocksthe airway 3940 partially or completely, the pressure drop across thepillow portion 3900 increases making it harder for a user to breathethrough the pillow portion 3900. The ribs 3901 help to stiffen the capand may act as load bearing members as the cap 3950-1 deforms wheninserted into a patient's nostrils, thus reducing or stopping the cap3950-1 from collapsing into the airway 3940. This makes it easier forthe patient to breathe through the pillow portion 3900 and cap 3950-1when in use and thus makes it more comfortable and safer for the patientto use the cap and pillow portion.

A further embodiment of the pillows portion is shown in FIGS. 40a, 40band 40c . In this variation, the pillows portion is shown as being usedwith the pillow gasket 250-2. However, the pillow portion may be usedwith the pillow gasket portion 350-2 or pillow gasket portion 450-2, asoutlined above. The pillow section 4050 is formed from the pillowportion and pillow gasket in combination.

This embodiment is formed from the same elements as form the thirdgeneral form of the pillows portion (described above), with specificdifferences as described below.

In the preferred embodiment the walls the cap 4050-1 taper in crosssectional thickness as best seen in FIG. 40c . The walls of the cap4050-1 are thicker at the lower end than at the upper end. The wall ofthe cap 4050-1 is thicker at the base 4004 than at the rim 4006 of thecap 4050-1. Alternatively the cross-sectional thickness of the walls ofthe cap may be constant.

The inside wall of the cap 4050-1 comprises at least one, but morepreferably a series of ribs 4001. Each of the rib or ribs 4001 ispreferably located on the inside surface of the wall of the cap 4050-1and extends from just above the base of the cap 4050-1 to the top rim ofthe cap 4050-1, as seen in FIG. 40c . In the preferred form the ribextends from the top edge of the cap 4050-1 (or just below the top edgeof the cap 4050-1) to just above the base of the cap 4050-1. Inalternative forms the rib 4001 could extend from just above the base tojust below the rim, without reaching either the base or the rim. In themost preferred form the rib 4001 is shaped to follow the contour of theinside wall of the cap 4050-1, as seen in FIG. 40c . Alternatively theouter edge of the rib 4001 may follow a curved path different to that ofthe inside wall of the cap 4050-1. The rib 4001 is preferably thicker atits mid-point than at its extremes (top and bottom). The rib 4001 at itsthickest point may be the same thickness of thicker than the crosssectional thickness of the wall of the cap 3950-1. In the most preferredform the rib 4001, at its thickest point, is the same thickness as thecap wall, at the cap wall's base. Alternatively the rib 4001 may taperin thickness, for example the rib 4001 may be thicker at its base thanat its rim, or vice versa. In a further alternative form the rib 4001may be of constant cross-sectional thickness along its entire height.

If a series of ribs 4001 are used, they are preferably all identical toeach other. In the preferred form the ribs 4001 are positioned atregular intervals around the perimeter of the inside surface of the cap4050-1. Alternatively the ribs 4001 may be placed at irregular intervalsaround the perimeter of the inside surface of the cap 4050-1. Preferablyall the ribs 4001 extend the same length or height within the cap4050-1. Alternatively the various ribs 4001 may extend varying distancesalong the height of the cap 4050-1. Having varying intervals and varyingextensions along the height can help to add strength at specific weakpoints on the cap 4050-1. If multiple ribs are used, it is preferredthat the tops are in the same plane and the bottoms are in the sameplane. Alternatively the top and the bottom of the ribs may be out ofplane. In the most preferred form the ribs 4001 are all of the samecross-sectional thickness as each other. However, it is conceivable thatthe ribs may vary in thickness from rib to rib. Further each rib 4001may be thicker at differing points along its height when compared to theother ribs.

The addition of the rib 4001, and more preferably a series of ribs helpsstrengthen or stiffen the cap 4050-1 wall. The added stiffness, inparticular added flexural stiffness, can help to reduce the amount ofdeformation of the cap 4050-1, as the cap is fitted into a patient'snostrils. The addition of the ribs 4001 adds stiffness while allowingthe cap 4050-1 to maintain at least substantial flexibility. The cap4050-1 being substantially flexible allows the cap 4050-1 to conform toa patient's nostrils in use and allows the cap 4050-1 to be fitted witha variety of users nostril shapes.

The addition of the rib 4001 around the perimeter of the cap 4050-1helps to stiffen and strengthen the cap 4050-1 so that it does notcollapse onto itself and block the airway 4040. If the cap 4050-1 blocksthe airway 4040 partially or completely, the pressure drop across thepillow portion increases making it harder for a user to breathe throughthe pillow portion. The ribs 4001 can help to stiffen the cap and theycan act as load bearing members as the cap 4050-1 deforms when insertedinto a patient's nostrils, thus reducing or stopping the cap 4050-1 fromcollapsing into the airway 4040. This makes it easier for the patient tobreathe through the pillow portion and cap 4050-1 when in use and thusmakes it more comfortable and safer for the patient to use the cap andpillow portion.

A further embodiment of the pillows portion is shown in FIGS. 41a, 41band 41c . In this variation, the pillows portion is shown as being usedwith the pillow gasket 250-2. However, the pillow portion may be usedwith the pillow gasket portion 350-2 or pillow gasket portion 450-2, asoutlined above. The pillow section 4150 is formed from the combinationof the pillow portion and the pillow gasket.

This embodiment is formed from the same elements as form the thirdgeneral form of the pillows portion (described above), with specificdifferences as described below.

In the preferred form the walls of the cap 4150-1 taper in crosssectional thickness as best seen in FIG. 41c . The walls of the cap4150-1 are thicker at the lower end than at the upper end. The wall ofthe cap 4150-1 is thicker at the base 4104 than at the rim 4106 of thecap 4150-1. Alternatively the thickness of the walls of the cap may beconstant or the wall thickness of one of the walls may taper while thewall thickness of the other wall may remain constant.

The cap 4150-1 has at least one “rib” feature. The rib feature ispreferably a solid fin 4101, as seen in FIGS. 41a and 41b . The fin 4101is preferably substantially diametrically aligned across the pillowportion. The fin 4101 extends from a position at or close to the topedge or rim 4107 of the cap 4150-1 downwardly. In the most preferredform the fin extends approximately three quarters of the way down theheight of the cap 4150-1. Alternatively the fin 4101 may extend from therim 4107 of the cap to the base 4104 of the cap 4150-1. Preferably thefin is aligned substantially vertically or upright in use. Alternativelythe fin may be curved in the vertical or horizontal plane. As outlinedabove, the fin 4101 is preferably substantially diametrically alignedacross the pillow portion. However, the fin 4101 may be offset to oneside of the cap 4150-1. In the most preferred form the fin is alignedand sized to bisect the upper opening of the cap 4150-1, with the finhaving straight sides, as seen in FIG. 41a . In alternative forms, thefin may be curved or have curved side walls. Preferably the lower orbottom edge of the fin 4101 is curved upwards as best seen in FIG. 41 c.

The fin 4101 is preferably thicker than the cap 4150-1 wall (greatercross-sectional thickness). In the most preferred form the fin 4101 istwice the thickness of the cap 4150-1 wall. Alternatively the fin 4101may be thinner in cross-section than the wall of the cap. Preferably thethickness of the fin 4101 is constant over the entire height of the fin4101. Alternatively the thickness of the fin 4101 may taper—the fin 4101may be thicker at its base than at its top edge, or vice versa. Thelateral thickness or width, the dimension labelled A on FIG. 41a ispreferably uniform. That is, the lateral cross section (dimension A), isuniform from one side of the cap 4150-1 to the other side of the cap4150-1, although the thickness may differ at different heights of thefin.

The addition of the fin 4101 helps to strengthen or stiffen the entirecap 4150-1 while still allowing the sides of the cap 4150-1 to besubstantially flexible. The added stiffness helps to reduce the amountof deformation of the cap 4150-1, as the cap is fitted into a patient'snostrils. The sides of the cap 4150-1 not engaged to the fin 4101 aresubstantially flexible, and this allows the cap 4150-1 to conform to apatient's nostrils in use and allows the cap 4150-1 to be fitted with avariety of users nostril shapes.

The addition of the fin 4101 to the cap 4150-1 helps to stiffen andstrengthen the cap 4150-1 so that it does not collapse onto itself andblock the airway 4141. If the cap 4150-1 blocks the airway 4140partially or completely, the pressure drop across the pillow portionincreases, making it harder for a user to breathe through the pillowportion. The fin 4101 helps to stiffen the cap and acts as a loadbearing member as the cap 4150-1 deforms when inserted into a patient'snostrils, thus reducing the amount the cap 4150-1 collapses into theairway 4140. This makes it easier for the patient to breathe through thepillow portion and cap 4150-1 when in use and thus makes it morecomfortable and safer for the patient to use the cap and pillow portion.

If the fin 4101 has tapered thickness over the height of the cap 4150-1,this provides the advantage of directing airflow out of the opening ofthe pillow. The fin 4101 is preferably thicker at its base than at itsrim. The tapering thickness assists in gently directing airflow or astream of gases towards the opening in the cap 4150-1 and helps tomaintain a low pressure drop across the pillow portion and the cap4150-1 when the cap 4150-1 is inserted into a patient's nostril.

A further embodiment of the nasal pillow portion is shown in FIGS. 42a,42b and 42c . This embodiment is the same as that described above withreference to FIGS. 41a-c , with specific differences as follows:

In this embodiment, the fin 4250-1 is wider at the sides than in thecentre. That is, towards the inner surface of the walls of the cap, thecross-sectional thickness of the fin 4250-1 increases. The fin 4250-1 iswider at the sides than in the centre.

A further embodiment of pillow portion is shown in FIG. 43. The figureonly shows only one pillow portion 4300 of what would normally be a pairused together. A pair of pillow portions would normally be used with apillow gasket 250-2 (not shown). The pillow portions could also be usedwith other pillow gaskets such as gaskets 350-2 and 450-2.

As can be seen in FIG. 43, the pillow portion is formed from a cap4350-1 and a stalk 4350-1. The cap 4350-1 is wider than the stalk4350-3. The walls of the cap 4350-1 taper in cross sectional thickness,as seen in FIG. 43. The wall of the cap 4350-1 is thicker at its base4304 than at the rim 4307. Alternatively, the wall of the cap 4350-1 maybe uniform in thickness. Preferably the thickness of the cap 4350-1 wallat its base 4304, is the same thickness or thicker than the wallthickness of the stalk 4350-3. Alternatively the wall of the stalk4350-3 may be thicker than the wall of the cap 4350-1 along all pointsof the cap 4350-1.

The cap 4350-1 has a bead 4301, located on the cap 4350-1, as seen inFIG. 43. The bead 4301 extends outward from the outer surface of the cap4350-1. Most preferably the bead 4301 is located at the rim 4307 of thecap 4350-1 and extends around the rim 4307. Alternatively the bead 4301may be located anywhere in the upper third of the outer surface of thecap 4350-1.

Preferably the bead 4301 extends continuously around the perimeter ofthe cap 4350-1. Preferably the bead 4301 extends uniformly around theperimeter of the cap 4350-1—the bead 4301 forms a continuous ring withno breaks. Also, it is preferred that the cross-sectional thickness ofthe bead is constant. Preferably the bead follows a symmetrical patharound the perimeter of the cap 4350-1. Alternatively the bead 4301 mayfollow any path along the outer surface of the cap 4350-1 perimeter—thatis, not strictly following the upper rim 4307, but dipping below this ifrequired. Furthermore, the bead 4301 may be formed discontinuouslyaround the perimeter or the rim if required.

Preferably the bead 4301 is circular in cross section. Alternatively thebead 4301 may be any other suitable cross section, for examplerectangular, triangular or elliptical. The bead 4301 is preferablythicker than the cross sectional thickness of the cap 4350-1 wall at therim 4307. More preferably the bead 4301 is twice the cross sectionalthickness of the cap wall at the rim 4307. Alternatively the bead 4301may be the same thickness or thinner than the cross sectional thicknessof the cap wall at its rim 4307. Preferably the thickness of the bead4301 is uniform or constant along its perimeter. Alternatively thethickness of the bead 4301 may vary along its perimeter, the thicknessof the bead being different from point to point along its perimeter. Thecross section of the bead 4301 is preferably constant along theperimeter of the cap 4350-1. Alternatively the cross section of the bead4301 may vary around the perimeter of the cap 4350-1. The variation inthickness or cross section or both can help to provide improved strengthor flexibility where required around the perimeter of the cap 4350-1.

Surprisingly it has been found that the addition of the bead 4301 to theouter surface of the cap 4350-1 helps to strengthen or stiffen the toppart or rim 4307 of the cap 4350-1. The added stiffness, in particularflexural stiffness, to the top part or rim 4307 helps prevent the rim4307 or top part of the cap 4350-1 from collapsing and blocking theairway 4340 and restricting the flow of gases out of the airway 4340 andthe cap 4350-1, while fitting the cap 4350-1 into a patient's nostrils.This provides the advantage of keeping the exit orifice 4320 as large aspossible while the cap 4350-1 is being fitted into a patient's nostrils.Preventing the airway 4340 or exit orifice 4320 from being blockedreduces the amount of pressure drop across the pillow portion 4300, andreduces the effort required by a patient to exhale through the cap4350-1. This provides the advantage of added comfort for the patient andease of breathing for the patient while using and fitting the pillowportion 4300.

The bead 4301 is purposely placed on the outer surface of the cap 4350-1so that the bead is out of the path of the gases travelling through theairway 4340. This helps reduce the amount of pressure drop across thepillow portion 4300 and cap 4350-1. Reduced pressure drop across the cap4350-1 and pillow portion 4300 is advantageous as it makes it easier fora patient to breathe normally and makes using the pillow portion 4300more comfortable.

It has surprisingly been found that while the bead 4301 may strengthenor stiffen the top part or rim 4307 of the outer cap 4350-1, the lowerpart of the outer cap 4350-1 remains substantially flexible and supple.This flexibility and suppleness allows the outer cap 4350-1 to distortto fit into a variety of nostril shapes and form an effective seal. Thisallows this particular type of pillows portion 4300 and caps 4350-1 tobe used with a variety of users to create an effective seal, whiledelivering therapy gases.

A further embodiment of pillow portion is shown as pillow portion 4400in FIG. 44.

As outlined above, a pair of pillow portions is normally used with apillow gasket such as pillow gasket 250-2. The pillow portion 4400 issimilar to pillow portion 4300 described above. The pillow portion 4400can also be used as one of a pair with pillow gasket 350-2 or 450-2,these gaskets being described earlier in the specification.

In this embodiment, the wall of the cap 4450-1 tapers in thickness. Mostpreferably the wall of the cap 4450-1 is thicker at the rim 4407 than atthe base 4404 of the cap 4450-1. The wall of the cap 4450-1 follows auniform cross section from the base 4404 toward the rim, with the wallof the cap beginning to thicken in the upper one fifth of the cap, thecap wall being thickest at the rim 4407. Alternatively the base 4404 ofthe cap 4450-1 may be the same thickness as the rim 4407, while themiddle or centre portion of the cap wall between the base and the rim isthinner than the rim and the base. In this alternative form the wall ofthe cap begins to thicken at the base 4404, becoming thinner as itapproaches the middle and then becoming thicker again as it approachesthe rim 4407, with the wall becoming thickest at the rim 4407.

A pillow portion with the features outlined above provides many of thesame advantages as those outlined above in relation to the pillowportion described in relation to FIG. 43. However, the constructiondiffers from that described for FIG. 43.

A further embodiment of pillow portion is shown in FIG. 45.

The pillow portion 4500 is similar to the pillow portion 4300, withspecific structural differences as outlined below. The pillow portion4500 may be used with any one of the pillow gaskets described above(250-2, 350-2 or 450-2), or any other suitable device.

In this embodiment of the pillow portion, the cross sectional thicknessof the wall of the cap 4550-1 is uniform along the height of the cap4550-1, as seen in FIG. 45. In a less preferred form the thickness ofthe wall of the cap 4550-1 may taper. For example the wall thickness atthe base 4504 may be greater than at the rim 4507 or vice versa.

The cap 4550-1 has a bead 4501 located on the inner wall of the cap4550-1. The bead is preferably located at and extends around the rim4507 of the cap 4550-1. Alternatively the bead 4501 may be located belowthe rim 4507 of the cap 4550-1. Preferably the bead 4501 is symmetricalat all points around the perimeter of the cap 4550-1, meaning the beadhas a uniform cross-section around the entire perimeter of the pillowportion. In the most preferred form the bead 4501 is located at the samevertical position on the inner surface of the wall of the cap path atall points around the perimeter of the cap 4550-1. In alternativearrangements the bead may follow an asymmetrical path around theperimeter of the cap 4550-1—that is, at any one point it may be below orabove another point at a different location. It should be noted that theword ‘vertical’ is used to indicate the position of the bead between therim and the base of the cap. The cap may not be aligned with the centralaxis vertical (the cap may be at an angle) as has been outlined above.

FIG. 45 shows the preferred form of the bead 4501, in which the bead4501 has a substantially semi-circular cross section. Alternatively thebead 4501 may have any other cross section shape, for example arectangular or oval cross section. The cross section shapes identifiedare only examples and should not be construed as limiting, since manyshapes for the bead 4501 would suggest themselves to a person skilled inthe art once they have read the description above. Preferably the bead4501 is thicker in cross sectional thickness than the cross sectionalthickness of the wall of the cap 4550-1, as best seen in FIG. 45. Evenmore preferably the bead 4501 is twice as thick as the wall of the cap4550-1. Alternatively the thickness of the bead may be thinner than thethickness of the wall of the cap 4550-1. Preferably the thickness of thebead 4501 is uniform along the entire perimeter of the outer cap 4550-1.Alternatively the bead thickness may vary from point to point along theperimeter of the cap 4550-1. As a further alternative the bead 4501 maybe thicker at one end of the rim and thinner at the other end. Thevarying thickness of the bead 4501 may be due random errors causedduring the manufacturing processes or maybe deliberate to strengthencertain parts of the rim 4507

It has surprisingly been found that the addition of the bead 4501 to theinside wall of the cap 4550-1 adds strength and increased stiffness tothe upper section of the cap 4550-1, in particular the rim 4507 and thesurrounding area of the rim. The additional stiffness due to the bead4501 helps to stop or reduce the amount the cap 4550-1 collapses intothe airway 4540, while fitting the cap 4550-1 into a patient's nostrils.The cap 4550-1 flexes during fitting into a patient's nostrils. The loadon a cap from the patient's nostril can cause the cap to partially orcompletely collapse or bend and block the airway 4540 or exit orifice4520, if it were not fitted with a bead. Blockage of the airway ororifice restricts the amount of gases being delivered to a patient,increases the pressure drop across a cap and increases the difficulty ofbreathing through the cap. The bead 4501 helps to reduce or stop the cap4550-1 from collapsing into the airway 4540 and prevents the exitorifice 4520 from being blocked or closed. Hence sufficient amount oftherapy gases are delivered to the patient, there is less of a pressuredrop across the cap 4550-1 and this reduces the difficulty of breathingthrough the cap 4550-1 and pillows portion 4500. This leads to addedcomfort for the patient and effective therapy for the patient.

A further embodiment of the pillow portion is shown in FIG. 46.

This embodiment is substantially the same as that described above,except that the cap also has a second bead, below the first one. The cap4650-1 therefore has a pair of beads 4601 and 4602 located on the innerwall of the cap 4650-1, with bead 4601 being the same as bead 4501 inthe embodiment described above. Preferably both beads extend around theperimeter of the cap 4650-1 and both beads are located in the uppersection of the cap 4650-1, as seen in FIG. 46. The second bead or lowerbead 4602 extends from the cap wall around the perimeter of the cap4650-1 and is located in the upper third of the height of the cap4650-1. Preferably there is a space between the two beads. Preferablythe space between the two beads is between 2 mm and 25 mm.

In the most preferred form the two beads 4601 and 4602 are identical toeach other. Preferably both beads have a substantially semi-circularcross section. Alternatively both beads can have any other crosssectional shape, like a rectangular cross section, a triangular crosssection, an elliptical cross section and so on. The beads 4601, 4602 arepreferably twice the thickness of the wall of the cap 4650-1, and thebeads are preferably the same thickness as each other. Alternatively thebeads may both be the same thickness as the cap 4650-1 or both beads maythinner than the cap 4650-1 wall thickness. Preferably both beads aresubstantially parallel to each other along the perimeter of the cap4650-1. Alternatively the beads 4601 and 4602 may not be identical toeach other. Each bead may have a separate cross sectional shapes to eachother—for example the first bead 4601 may be circular in cross section,while the second bead 4602 may be rectangular in cross section and soon. The beads may vary in thickness from each other—meaning one bead maybe twice the thickness of the cap wall while the other bead may bethrice the thickness as the cap wall, or one bead may be thicker thanthe cap wall while the other bead may be thinner or the same thicknessas the cap wall, and so on. In a further alternative the beads may notextend parallel to each other around the perimeter of the cap 4650-1,meaning at least one of the beads may vary in vertical position alongthe internal wall. Most preferably the first bead 4601 is generallycircular around the perimeter of the cap 4650-1 and follows a straightcircular path, while the second bead 4602 preferably follows a moreelliptical path. The second bead 4602 may extend downward along the walltoward the stalk 4650-3 at some points along the perimeter of the capand then return to its original path. A variety of combinations areavailable for design by combining the various features described above.The above descriptions are general descriptions of preferred featuresand any combinations of these will suggest themselves to persons skilledin the art.

A further embodiment of the pillow portion is shown in FIGS. 47a, b ,and c.

In this embodiment, a pair of pillow portions is used in combinationwith pillow gasket 250-2, as shown in FIG. 47b . The pillow portionscould alternatively be used with other pillow gaskets such as pillowgaskets 350-2 and 450-2 described above. The pillow portion and pillowgasket in combination form the pillow section 4700 of this embodiment.

The pillow portions consist of an inner cap 4750-1 b and an outer cap4750-1 a, connected to a stalk 4750-3, with the base of the stalkfluidically or gaseously connected to the pillow gasket, and the innerand outer caps connected to the top of the stalk.

In the preferred form the wall of the inner cap 4750-1 b is uniform inthickness. The wall of the outer cap 4750-1 a is also uniform inthickness. Preferably the wall of the inner cap 4750-1 b is much thickerthan the wall of the outer cap 4750-1 a, as seen in FIG. 47c .Alternatively the wall of the inner cap 4750-1 b may taper in thickness,for example the wall of the inner cap 4750-1 b may be thicker at itsbase 4705 and thinner at its rim 4707, or vice versa. Alternatively thewall of the outer cap 4750-1 a may also be tapered in thickness, forexample the wall of the outer cap 4750-1 a may be thicker at its base4704 and thinner at its rim 4706, or vice versa. In a furtheralternative form the outer cap 4750-1 a may be thicker than the innercap 4750-1 b. Further alternatively the inner cap 4750-1 b may taper inthickness while the outer cap 4750-1 a may be uniform in thickness, orvice versa.

The outer surface of the inner cap 4750-1 b preferably has a continuousbead 4701 that extends along the top edge or rim 4707 of the inner cap4750-1 b, as best seen in FIGS. 47a and 47c . Preferably the bead 4701extends outward toward the outer cap 4750-1 a from the outer surface ofthe inner cap 4750-1 b as seen best in FIG. 47c . Preferably the bead4701 extends around the perimeter of the inner cap 4750-1 b. As afurther alternative the bead 4701 may extend around the perimeter of theinner cap 4750-1 b and may extend from any point between the base 4705and the rim 4707 of the inner cap 4750-1 b. The bead 4701 is preferablyhemispherical or semi-circular in shape. Alternatively the bead may beany other shape for example, rectangle, triangle or oval. The bead ispreferably of constant thickness along the entire length of the bead.Alternatively the bead may vary in thickness along the perimeter of theinner cap 4750-1 b. In the alternative form the bead 4701 may bediscontinuous along the perimeter of the inner cap 4750-1 b. The bead4701 may only be applied to areas of the inner cap 4750-1 b that areweaker. In a further alternative form the bead 4701 may change shape atdiffering points along its perimeter, for example the bead 4701 may becircular along part of its length and then change to a triangular shapefor another part of its length, and so on.

The outer surface of the inner cap 4750-1 b also includes at least one,but preferably a plurality of openings 4702 around the outer surface ofthe inner cap 4750-1 b, as seen in FIG. 47a . The openings 4702 arepreferably circular. Alternatively the openings may be elliptical, oval,square or any other suitable shape. The openings 4702 are preferablypositioned at regular intervals around the outer surface of the innercap 4750-1 b. Alternatively the openings 4702 may be positioned atirregular intervals around the inner cap 4750-1 b. The openings are cutinto the inner cap 4750-1 b by any suitable process, for example millingor the like. Preferably the openings 4702 are all identical to eachother. Alternatively the openings 4702 may be different from each other.The diameter or size of the hole in the opening 4702 may vary fromopening to opening in an alternative form. The above descriptions aregeneral descriptions of features and any combination of the describedfeatures is possible and falls within scope the invention.

Surprisingly it has been found that the addition of the bead 4701 to theinner cap 4750-1 b strengthens or stiffens the upper section or rim areaof the inner cap 4750-1 b. The added strength or stiffness reduces theamount by which the inner cap 4750-1 b collapses while the cap 4750-1 isbeing fitted to a patient's nose. Generally as the cap is being fittedinto a patient's nose the cap deforms to conform to the shape of thepatient or user's nostril shape. The deformation of the cap causes theouter cap 4750-1 a and the inner cap 4750-1 b to deform. Often the innercap 4750-1 b can deform and collapse into the airway 4740. The collapseof the inner cap 4750-1 b into the airway 4740 can cause the airway 4740to be completely or partially blocked. The blocked airway restricts theamount of gases flowing to the patient. This can lead to less gasesbeing delivered to the patient and can lead to incorrect or ineffectivetherapy for the patient. The blocking or partial blocking of the airway4740 can also increase the pressure drop across the entire pillowsection, making it harder for a patient to breathe through the pillowsportion. The added strength or stiffness to the upper part of the innercap 4750-1 b, due to the bead 4701, reduces the amount the inner cap4750-1 b collapses while fitting the pillows portion into the nostril ofa patient. The reduced collapse of the inner cap 4750-1 b, in particularthe upper region of the inner cap 4750-1 b, leads to the airway beingopen while fitting the pillows portion into a patient's or user'snostrils. This leads to a reduced pressure drop across the pillowsection and makes it easier for a patient to breathe through the pillowsportion or pillow section, leading to added comfort for the patient.Further the reduced blocking of the airway 4740 leads to more gasesbeing delivered to a patient or user, leading to more effective therapydelivered to a patient.

Surprisingly it has also been found that the bead 4701 can act as a seator support for the outer cap 4750-1 a as the outer cap 4750-1 adepresses or deforms as it is being fitted into the nostrils of apatient or user. The bead 4701 acts to support and reduce the amount theouter cap 4750-1 a collapses into the inner cap 4750-1 b. The bead 4701acts as a load bearing support to support the weight of the outer cap4750-1 a as it collapses or deforms when being fitted.

Surprisingly it has also been found that by having the openings 4702 atleast some of the air flowing through the airway 4740 can flow into theair gap 4710 or air space between the outer cap 4750-1 a and inner cap4750-1 b. The bead 4701 acts to seal the air gap 4710 if the outer cap4750-1 a, in particular the upper part of the upper cap 4750-1 a,deforms or collapses onto the bead 4701, while fitting the cap to into apatient's nostrils or in use. If the outer cap 4750-1 a does deform onto the bead 4701 the air flowing into the air gap 4710 can partiallyinflate the lower part of the outer cap 4750-1 a. The partial inflationof the outer cap 4750-1 a allows the outer cap 4750-1 a to contort andadapt to different shaped nostrils and provide a more effective sealwith the users nostrils. In particular the partially inflated lower partof the outer cap 4750-1 a, allows the upper part of the outer cap 4750-1a to contort and adapt to different shaped nostrils while letting theinflated lower part of the outer cap 4750-1 a form a more effective sealwith the nostrils of a user. This is advantageous as an effective sealleads to more effective therapy being delivered to a patient.

A further embodiment of the pillow portion is shown in FIGS. 48a, b ,and c.

The embodiment shown in FIGS. 48a-c is identical to the embodiment (andvariants thereof) described above in relation to FIGS. 47a-c , withstructural differences as outlined below.

The outer surface of the inner cap 4850-1 b also has at least one, andpreferably a series of, ribs 4803 extending outward from the outersurface of the inner cap 4850-1 b towards the inner surface of the outercap. The ribs 4803 extend into the air gap 4810. Most preferably thereare four ribs 4803 on the outer surface of the inner cap 4850-1 b,interspersed between the openings 4802. Alternatively there may be anynumber between one and ten ribs 4803 placed on the outer surface of theinner cap 4850-1 b. The ribs preferably extend from the bead 4801 to thebase 4805 of the inner cap 4850-1 b.

Alternatively the ribs 4803 may extend any distance along the outersurface of the inner cap 4850-1 b. In a further alternative the ribs4803 may extend from below the bead 4801 to just above the base 4805, orany point there between. Preferably all the ribs are identical to eachother. Preferably the ribs 4803 all extend the same distance along theouter surface of the inner cap 4850-1 b. However alternatively thedistance the ribs 4803 extend down the outer surface of the inner cap4850-1 b may vary from rib to rib. The ribs 4803 are preferablyrectangular in cross-section. Alternatively the ribs may be any othersuitable shape. The ribs are preferably placed at regular intervalsaround the outer surface of the inner cap 4850-1 b. Even more preferablyeach rib 4803 is placed between two openings 4802, as seen in FIG. 48a .Alternatively the ribs 4803 may be placed at irregular intervals alongthe outer surface of the inner cap 4850-1 b. As a further alternativethe number of ribs 4803 between openings 4802 can vary. The ribs arepreferably the same thickness as each other. Most preferably the ribsare twice the thickness of the outer cap 4850-1 a wall thickness.Alternatively the ribs 4803 may be thinner than the outer cap wall ormay be any other suitable thickness that fits between the inner cap4850-1 b and outer cap 4850-1 a. As a further alternative arrangementthe ribs may be added at specific points along the outer surface of theinner cap 4850-1 b, in order to strengthen certain areas of the innercap 4850-1 b.

It has also been found that the addition of the ribs 4803 to the outersurface of the inner cap 4850-1 b helps to strengthen or stiffen theinner cap 4850-1 b. This added strength or stiffness further reduces theamount the inner cap 4850-1 b collapses or deforms while fitting the capinto a patient's nostrils. The ribs 4803 also act as a further supportfor the outer cap 4850-1 a and support the outer cap as it deforms orcollapses. The ribs 4803 support the outer cap 4850-1 a and stop it fromcollapsing into the inner cap 4850-1 b. The ribs support the cap in amanner that still allows the outer cap 4850-1 a to be partially inflatedby air entering the air gap 4810, and retaining the advantages describedearlier in relation to the embodiment described with reference to FIGS.47a -c.

A further embodiment of the pillow portion is shown in FIGS. 49a, b ,and c.

The embodiment shown in FIGS. 49a-c is identical to the embodimentsdescribed above in relation to FIGS. 47a-c , and FIGS. 48a-c , withspecific structural differences as outlined below.

The embodiment shown in FIGS. 49a-c also includes at least one andpreferably a series of ribs. In this variation or embodiment, the ribs4903 are curved in profile, as seen in FIG. 49a . The ribs 4903 curve ina generally C shape when viewed in plan, as seen in FIG. 49a . The ribs4903 curve outward from the top of the rib and curve inward toward thebase of the rib, such that the top and base of rib 4903 are co-axial.Alternatively the ribs 4903 may be substantially S shaped.

A further embodiment of pillow portion is shown in FIGS. 50a, b and c.

In the embodiment of FIGS. 50a-c , a pair of pillow portions is usedwith pillow gasket 250-2, as shown in FIG. 50a . Alternatively, thepillow portions could be used with pillow gaskets 350-2 or 450-2. Thepillow portion and pillow gasket in combination form a pillow section5000.

This embodiment is formed from the same elements as form the thirdgeneral form of the pillows portion (described above), with specificdifferences as described below.

The pillow portion shown in FIGS. 50a-c comprises a stalk 5050-3 and acap portion 5050-1. Preferably each stalk 5050-3 also has at least one,but more preferably a plurality of ribs 5001 extending outwardsubstantially perpendicularly to the body of the stalk(s), from theouter surface of the stalks 5050-3, as seen best in FIG. 50c . The ribsare preferably elongate extensions with rounded (hemispherical) ends.The ribs 5001 are preferably positioned at substantially the midpoint ofeach of the stalks 5050-3. Alternatively the ribs 5001 may be positionedat the base of the stalks 5050-3 or at the top of the stalk 5050-3. Theribs 5001 in the preferred form extend from the centre of the stalk5050-3 outward and do not contact any other surface except the centre ofthe stalk 5050-3, when the apparatus is not in use.

Preferably there are two ribs 5001. Each of the ribs 5001 are preferablyidentical to each other in height, width and thickness. Alternativelythe ribs 5001 may vary in height, thickness and width from each other.The ribs 5001 are preferably placed at regular intervals around theperimeter of the stalk 5050-3—i.e. if two only are used they are placedat diametrically opposed positions. Alternatively the ribs 5001 may beplaced at varying or irregular intervals around the perimeter of thestalk 5050-3.

The purpose of the ribs is to strengthen the stalk 5050-3 whilemaintaining the flexibility of the stalks 5050-3. The stalks 5050-3 flexand contort as the cap 5050-1 is being fitted into the nostrils of thepatient. The flexing of the stalk 5050-3 helps the cap to conform to theshape of a user's nostrils and form an effective seal. The stiffnessadded by the ribs 5001 allows the stalk 5050-3 to hold its shape oncethe cap 5050-1 is fitted into a user's nostril, thus allowing for a moreeffective seal. The strength and stiffness provided by the ribs 5001 tothe stalk 5050-3 allows the stalk 5050-3 to exert a greater forceagainst the face of a users leading to a more effective seal beingformed with a user's face. The combination of flexibility of the stalk5050-3 and stiffness from the ribs 5001 allows the stalks, and hence thecap to form a more effective seal with the user's nostrils. A moreeffective seal with a users nostrils results in more effective therapybeing delivered to the patient or user.

The ribs 5001 are out of the pathway of the gases and hence they do notact to cause resistance to the flow of gases as the gases pass throughthe stalk 5050-3 and out of the cap 5050-1. Surprisingly it has beenfound that the ribs act to provide a suitable stiffness to the pillowportion, but do not adversely affect the ability of a user to breathethrough the pillow portions. Further the added stiffness of the stalk5050-3, reduces or prevents the stalk 5050-3 from collapsing anddeforming. The reduced deformation means the airway 5040 remains openand unrestricted. The open airway 5040 reduces the pressure drop acrossthe pillow portions and makes it easier for a patient to breathe throughthe pillow portion.

Surprisingly it has been found that the rib 5001 also acts to supportthe cap 5050-1 as it deforms or contorts while in use. The cap 5050-1can deform or contort until the base of the cap 5050-1 rests on the ribs5001. The support provided by the ribs 5001 limits the amount the cap5050-1 deforms while in use leading to a more effective seal beingformed between the cap 5050-1 and the nostrils of a user.

A further embodiment of the pillows portion is shown in FIGS. 51a, b andc.

The pair of pillow portions shown in FIGS. 51a-c is used with pillowgasket 250-2, as shown in FIG. 50a . However, the pillow portions can beused with pillow gaskets 350-2 or 450-2, as described earlier. Thepillow portion and pillow gasket in combination form the pillow section5100.

The embodiment as shown in FIGS. 51a-c is substantially the same as theembodiment described above in relation to FIGS. 50a-c . The pillowportion comprises a stalk 5150-3 and a cap portion 5150-1. Preferablyeach pillow portion also has at least one, but more preferably aplurality of ribs 5101. The ribs 5101 preferably extend outward in asubstantially perpendicular manner from the outer surface of the stalks5150-3. The ribs preferably extend outwards from the base of the stalk,where the stalk is connected to the gasket. Although in the preferredform the ribs are connected to or are formed integrally with the stalk,it can be seen that they could also be formed integrally with or beconnected to the gasket, extending upwards from the gasket in the samedirection as the axis of the stalk. Preferably the ribs 5101 extendupward for around one-third of the height of the stalk. If a pair ofribs are used, it is preferred that the outer edge of one of the ribs5101 curves away from the centre of the stalk 5150-3 (see feature A inFIG. 51c ), and the outer edge of the other rib curves toward the centreof the stalk 5150-3 (see feature B, FIG. 51c ). It is preferred that apair of ribs are used, and that they are located so as to bediametrically opposed around the stalk. The ribs 5101 are preferablyidentical to each other in height, width and thickness. Alternativelythe ribs 5101 may vary in height, thickness and width from each other.

As the cap is placed into the nostril of a user, the stalk will compressand the base of the stalk will contact the upper surface of the rib orribs. The ribs will act to support the cap, and to assist in stoppingthe cap and the stalk from collapsing. This provides advantages similarto those outlined above for the embodiment described in relation toFIGS. 51a -c.

A further embodiment of pillows portion is shown in FIGS. 52a -c.

In this embodiment, a pair of pillow portions is used with pillow gasket250-2, as shown in FIG. 50a , although the pillow portion could also beused with pillow gaskets 350-2 or 450-2. The pillow portion and pillowgasket in combination form the pillow section 5200.

The embodiment as shown in FIGS. 52a-c comprises a stalk 5250-3 and acap portion 5250-1 connected to a gasket (e.g. gasket 250-2) so thatgases can flow between the two.

The embodiment shown in FIGS. 52a-c is substantially the same as thatdescribed above in relation to FIGS. 50a-c , except that the rib or ribsare located directly under the base of the cap rather than at the pointwhere the stalk is connected to the gasket. The rib or ribs 5201preferably extend outward from the outer surface of the stalks 5250-3,as seen best in FIG. 52c . The ribs are preferably elongate extensions.In the preferred form the ribs are integrally formed with both the stalkand the underside of the base of the cap. In the preferred form theheight of the ribs 5201 is substantially half the height of the stalk5250-3.

Preferably the ribs 5201 are positioned around the perimeter of thestalk 5250-3. It is preferred that a pair of ribs is used, and that theribs 5201 are identical to each other in height, width and thickness.Alternatively the ribs 5201 may vary in height, thickness and width fromeach other. The ribs 5201 are preferably placed at regular intervalsaround the perimeter of the stalk 5250-3. Alternatively the ribs 5201may be placed at varying or irregular intervals around the perimeter ofthe stalk 5250-3. If a pair of ribs is used, it is most preferred thatthese are placed at diametrically opposed positions around the stalk.

Having the ribs directly underneath the cap at the top of the stalk,rather than directly over the gasket and at the bottom of the stalk,provides the same advantages as have already been outlined in relationto the embodiment described with reference to FIGS. 51a-c . As the stalkis compressed in use, the rib or ribs act to support the stalk and to acertain extent the cap, and help to prevent the collapse of the stalk orthe cap or both.

A further embodiment of the pillow portion is shown in FIGS. 53a, b andc.

A pair of pillow portions is used with pillow gasket 250-2, as shown inFIG. 53a . The pillow portions can also be used with pillow gaskets350-2 or 450-2.

The pillow portion and pillow gasket in combination form a pillowsection 5300.

The embodiment of pillow portion as shown in FIGS. 53a-c comprises astalk 5350-3 and a cap portion 5350-1, the lower end of the stalkconnecting to the pillow gasket in such a manner that gases can flowfrom the gasket to the stalk, and the cap portion connected to the upperend of the stalk. In this embodiment, each stalk 5350-3 has at leastone, and preferably a plurality of ribs 5301 which are located on theoutside of the stalk. The ribs 5301 preferably extend outward from theouter surface of each of the stalks 5350-3, as seen best in FIG. 53c .The ribs are curved in shape with a flat outer surface or edge (furthestfrom the stalk). More preferably the ribs 5301 are crescent shaped whenviewed in a side view. Preferably the body of the rib 5301 is at leastpartially concave, as seen in FIG. 53c (feature Z). The ribs 5301 extendbetween the underside or base of the cap 5350-1 and the base of thestalks 5350-3 (the upper surface of the gasket). Preferably the ribs5301 are the same thickness as the wall of the cap 5350-1. Alternativelythe ribs may be half the thickness of the cap wall. As a furtheralternative the rib or ribs 5301 may be thinner than the cap wall orless than half the thickness of the cap wall.

Preferably the ribs 5301 are positioned around the perimeter of thestalk 5350-3, at generally equidistant intervals. The ribs 5301 arepreferably identical to each other in height, width and thickness.Alternatively the ribs 5301 may vary in height, thickness and width fromeach other. The ribs 5301 are preferably placed at regular intervalsaround the perimeter of the stalk 5350-3. Alternatively the ribs 5301may be placed at varying or irregular intervals around the perimeter ofthe stalk 5350-3.

The purpose of the rib or ribs 5301 is to strengthen the stalk 5350-3while maintaining the flexibility. The stalks 5350-3 flex and contort asthe cap 5350-1 is being fitted into the nostrils of the patient. Theflexing of the stalk 5350-3 helps the cap to conform to the shape of auser's nostrils and form an effective seal. The stiffness added by theribs 5301 allows the stalk 5350-3 to hold its shape once the cap 5350-1is fitted into a user's nostril, thus allowing for a more effectiveseal. The strength and stiffness provided by the ribs 5301 to the stalk5350-3 allows the stalk 5350-3 to exert a greater force against the faceof a user leading to a more effective seal being formed with a user'sface. The combination of flexibility of the stalk 5350-3 and stiffnessfrom the ribs 5301 allows the stalks, and hence the cap to form a moreeffective seal with the user's nostrils. A more effective seal with ausers nostrils results in more effective therapy being delivered to thepatient or user.

It has been found that having the ribs on the outside of the stalk isbeneficial. The pressure drop across the pillow portion remains moreconsistent in use due to the ribs 5301 being on the outer surface of thestalk 5350-3. The ribs 5301 are out of the pathway of the gases andhence do not add to the flow resistance experienced by the gases as theypass through the stalk 5350-3 and out of the cap 5350-1. This can helpto make it easier for a user to breathe through the pillow portions.Further, the support added to the stalk helps to reduce or prevents thestalk 5350-3 from collapsing and deforming.

A further embodiment of the pillow portion is shown in FIGS. 54a -c.

A pair of pillow portions according to this embodiment can be used withpillow gasket 250-2, as shown in FIG. 54a . The pillow portions couldalso be used with pillow gaskets 350-2 or 450-2.

The pillow portion and pillow gasket in combination form a pillowsection 5300.

The embodiment of pillow portion as shown in FIGS. 54a-c comprises astalk 5450-3 and a cap 5450-1. Preferably each stalk 5450-3 also has atleast one, but more preferably a plurality of ribs 5401. The ribs 5401preferably extend outward from the outer surface of the stalks 5450-3,as seen best in FIG. 54c . The ribs 5401 extend between the underside ofthe cap 5450-1 and the base of the stalk 5450-3. The ribs 5401 spiralaround the stalk 5450-3 as the ribs extend down along the stalk 5450-3,as seen in FIGS. 54a and 54c . The ribs 5401 are preferably extend alongthe outer surface of the stalk in a spiral or helical shape. Preferablythe ribs 5401 on one stalk 5450-3 spiral in opposite directions to theribs 5401 on the opposite stalk 5450-3, as seen in FIG. 54a (clockwiseand anticlockwise). The ribs are arranged so that the helical angles ofone set of ribs on one stalk 5450-3 are opposite to the helical angle ofthe ribs on the other stalk 5450-3. The rib angles between two sets ofribs 5401 on two opposite stalks are effectively mirror images of eachother.

Preferably the ribs 5401 are positioned around the perimeter of thestalk 5450-3. Each of the separate ribs 5401 are preferably identical toeach other in height, width and thickness. Alternatively the ribs 5401may vary in height, thickness and width from each other. The ribs 5401are preferably placed at regular intervals around the perimeter of thestalk 5450-3. Alternatively the ribs 5401 may be placed at varying orirregular intervals around the perimeter of the stalk 5450-3. Preferablythe helical angle, meaning the amount the rib curves around the stalk,is the same from rib to rib. Alternatively the helical angle may varyfrom rib to rib. In the most preferred form there are three ribs thatextend between the underside of the cap 5450-1 and the base of the cap5450-3 on each of the pillow portions.

The purpose of the rib or ribs 5401 is to strengthen the stalk 5450-3while maintaining the flexibility of the stalks 5450-3. The stalks5450-3 flex and contort as the cap 5450-1 is being fitted into thenostrils of the patient. The flexing of the stalk 5450-3 helps the capto conform to the shape of a user's nostrils and form an effective seal.The stiffness added by the ribs 5401 allows the stalk 5450-3 to hold itsshape once the cap 5450-1 is fitted into a user's nostril, thus allowingfor a more effective seal. The strength and stiffness provided by theribs 5401 to the stalk 5450-3 allows the stalk 5450-3 to exert a greaterforce against the face of a users leading to a more effective seal beingformed with a user's face. The combination of flexibility of the stalk5450-3 and stiffness from the ribs 5401 allows the stalks, and hence thecap to form a more effective seal with the user's nostrils. A moreeffective seal with a users nostrils results in more effective therapybeing delivered to the patient or user.

This is substantially similar to the advantages described above inrelation to the embodiment shown in FIGS. 53a-c . The spiral ribs 5401to the outer surface of the stalks 5450-3 cause the stalk and cap torotate as the cap is depressed while fitting the cap 5450-1 into apatient's nostrils. The cap 5450-1 and stalk 5450-3 rotate due to theribs 5401 transmitting the force applied to the cap in a rotationaldirection due to the spiral shape of the ribs 5401. By varying thehelical angle of the ribs 5401 the force transmission can be varied andthe ribs can be angled so that the cap 5450-1 or stalk 5450-3 or bothrotate in only one direction. This is advantageous because rotationalmovement in a single direction allows for a better seal with a patient'snostrils since the deformation of the cap 5450-1 or stalk 5450-3 or bothis controlled. The rotational movement limits the lateral and axialdeformation of the cap 5450-1 or stalk 5450-3, thus allowing the cap andstalk to remain in the correct alignment, leading to a more effectiveseal being formed and more effective therapy being delivered to thepatient. The limited axial and lateral deformation of the cap 5450-1 orstalk 5450-3 or both also ensures that the airway 5440 remains unblockedsince the cap 5450-1 or stalk 5450-3 will rotate under load rather thancollapsing. The airway 5440 being unblocked leads to a reduced pressuredrop across the cap and stalk resulting in more comfort for the patientand easier breathing for the patient through the pillow section 5400 orpillow portion or both.

A further embodiment of the pillow portion is shown in FIGS. 55a-c . Theelements are substantially identical to those described above for theembodiment shown in FIGS. 54a-c . However, the ribs terminate at themiddle of the stalk 5550-3. That is, the ribs extend downwards from thetop of the stalk for approximately half the length of the stalk, ratherthan all the way to the base as described above for the embodiment ofthe FIGS. 54a -c.

A further embodiment of the nasal pillow portions is shown in FIGS. 56a,56b and 56 c.

In this variation the pillows portion is shown as being used with agasket portion 550-2. However the pillow portion can be used with otherpillow gasket portions such as 250-2, 350-2 and 450-2 described indetail above.

In a similar manner to pillow gasket portions 250-2, 350-2 and 450-2described in detail above, the pillow gasket portion 550-2 forms part ofa patient interface for receiving gases from a gases supply. The pillowgasket portion 550-2 has an open lower portion that receives gases froma conduit. The main portion of the gasket portion 550-2 comprises amanifold section. The manifold section of the gasket portion 550-2 has asubstantially flat top platform 5660, to which a pair of cap sectionsare attached. The cap sections will be described in detail below.Preferably the pillow portions 5650 are formed integral to the platform5660.

Preferably the pillow portions 5650 extend directly from the topplatform 5660. Each of the pillow portions 5650 has a base section5650-1 a that extends a short distance from the platform 5660, with acap 5650-1 b extending from the base section 5650-1 a. The base section5650-1 a and cap 5650-1 b together form the pillow portion 5650. Thebase section 5650-1 a can preferably maintain its shape when loaded in avertical direction. The base section 5650-1 a acts as the supportstructure for the cap 5650-1 b. The base section is shaped such that itresists compression, thus ensuring the entire pillow portion 5650-1 doesnot collapse and block the gases from reaching the user. The basesection 5650-1 a extends upwards (that is, substantially perpendicularto the surface of the top platform 5660) with parallel sides. The cap5650-1 b connects to the base section 5650-1 a at the round 5601, at theupper extreme of the base section 5650-1 a. The base section 5650-1 a ispreferably at least as wide or wider than the bottom of the cap 5650-1b.

The cap 5650-1 b is capable of deforming and flexing to fit the nostrilsof a user and create a seal. The cap 5650-1 b is shaped to guide gasesinto a patient's nostrils. The cap 5650-1 b has curved or sloping wallsthat narrow to an exit orifice 5610. Most preferably the cap 5650-1 b isshaped substantially like a bottle neck as seen in FIG. 56c —that is,funnel shaped. The base section 5650-1 a and cap 5650-1 b define anairway. The airway is a hollow pathway that passes through the basesection 5650-1 a and the funnel 5650-1 b and connects the orifice 5610to the platform. The airway allows gases flowing from the gasket 550-2to exit through the orifice 5610 by travelling through the airway. Thepillow portion 5650-1 preferably has a uniform wall thickness along theentire pillow portion 5650-1. Alternatively the thickness of the pillowportion wall may vary. The pillow portion wall may be thicker at thebase of the base section 5650-1 a and thinner at the rim of the cap5650-1 b.

The sides of the pillow portion extend outwards (funnel-shaped) to theedges of the upper part of the base section.

By extending the pillows support structure (the base section) so thatthe upper part merges or connects to the outer edge of the pillowportion, rather than having a stalk or stem which is narrower than thepillow and the pillow connecting to the stem, the opening or air paththrough the base section or pillow support structure to the cap is heldas open as possible and can be as wide as possible, which assists withminimising the pressure drop as gases pass through the pillows portion.As shown in FIG. 57b , the air path through the base and cap only beginsto narrow once it enters the cap—it does not widen as it enters the capas it does in the embodiments described above which use a stalk and acap. That is, the gases path through said base section and said cap isas wide as possible through said base section and at the point of entryto said cap. This assists in maintaining an unblocked airway and helpsto keep the orifice open in use and while the pillow portions are beingfitted into a patient's nostrils. Also, by having a base section 5650-1a extending directly from the platform (that is, no stalk) and havingthe base section wider and more rigid than the cap 5650-1 b, this canalso help to support the cap 5650-1 b as the cap contorts or deformswhile being fitted into a user's nostrils. The cap contorting ordeforming can cause the cap 5650-1 b to deform in such a way that theairway becomes blocked. A blocked airway causes an increased pressuredrop across the pillows portion 5650, resulting in increased breathingeffort by the user or patient. The increased breathing effort makes thepillows portion difficult and uncomfortable to use and results inineffective therapy. The increased breathing effort can also lead torespiratory problems and possible damage to the respiratory system of auser. The ability of the base section 5650-1 a to move laterally alsohelps to keep the orifice 5610 open and airway unblocked.

The base section 5650-1 a supports vertical loading and allows the capto contract (as explained above) and the base section 5650-1 a isflexible enough to move laterally in response of any forces with ahorizontal component. The lateral movement of the base section 5650-1 acauses the cap 5650-1 b to contract and move laterally to take the shapeof a user's nostril and maintain the orifice 5610 in an open position.The lateral movement allows the pillows portion 5650 as a whole toremain in the correct position as the user sleeps and moves. The lateralmovement of the base section 5650-1 a helps maintain the cap 5650-1 b inthe correct position to provide effective therapy. The lateral movementof the base section 5650-1 a allows the caps 5650-1 b to be fitted intonostrils with varying spacing between the nostrils. This allows thepillows portion 5650 to be more adaptive and allows the pillows portionsto be used with a variety of different shaped noses.

A further embodiment of the nasal pillow portions is shown in FIGS. 57aand 57 b.

The general form of the nasal pillows portion is the same as theembodiment described above with reference to FIGS. 56a and 56b , with astructural difference as follows: The base section 5750-1 a is shapedwith tapering sides that taper inward towards each other from the top ofthe base section (or outwards from the bottom of the base section), asseen in FIG. 57a . The bottom of the base section is therefore narrowerthan the top of the base section 5750-1 a. The gases path from thebottom of the base section to the bottom of the attached cap willtherefore widen from the bottom of the base section to the top.

This construction offers similar advantages to those described above forthe embodiment described with reference to FIGS. 56a and 56b . That is,it assists with minimising the pressure drop as gases pass through thepillows portion. The other advantages as outlined above also apply.However, the variation in the design also has the advantage that thestrength and flexibility is improved.

A further embodiment of the nasal pillow portions is shown in FIGS. 58aand 58 b.

The embodiment shown in FIGS. 58a and 58b is substantially similar tothat shown in FIGS. 56a-b, and 57a-b , with the following structuraldifference: The base section 5850-1 a has tapering sides that extendupwards from the gasket portion substantially parallel to each other,and then curve outwards before connecting to the cap, as seen in FIGS.58b and 58a . In appearance, there is a central bulge or wider sectionwhere the base section and the cap connect.

This construction offers similar advantages to those described above forthe embodiment described with reference to FIGS. 56a-b and 57a-b . Thatis, it assists with minimising the pressure drop as gases pass throughthe pillows portion. The other advantages as outlined above also apply.However, the variation in the design also has the advantage that thestrength and flexibility is improved.

A further embodiment of the nasal pillow portions is shown in FIGS. 59aand 59 b.

The embodiment shown in FIGS. 58a and 58b is substantially similar tothat shown in FIGS. 56a-b, 57a-b, and 58a-b , with the followingstructural difference: The base section 5950-1 a has tapering sides thattaper or angle inwards towards each other, so that the base section hasa wider bottom than top (where it is connected to the cap). This is bestseen in FIGS. 59a and 59b . The sides of the base section 5950-1 a areangled outward (from the top) such that the lower portion of the basesection 5950-1 a is wider than the upper portion of the base section5950-1 a.

This construction offers similar advantages to those described above forthe embodiment described with reference to FIGS. 56a-b and 57a-b . Thatis, it assists with minimising the pressure drop as gases pass throughthe pillows portion. The other advantages as outlined above also apply.However, the variation in the design also has the advantage that thestrength and flexibility is improved.

A further embodiment of the nasal pillow portions is shown in FIGS. 60aand 60b . The embodiment shown in FIGS. 58a and 58b is substantiallysimilar to that shown in FIGS. 56a-b, 57a-b, and 58a-b , with thefollowing structural difference: The base section 6050-1 a wall isrounded outwards at the centre so that the base section is wider at thecentral portion of the base section than at the upper and lower ends.That is, the base section 6050-1 a is wider at the middle of the basesection than at the upper and lower ends—the base section bulgesoutwards in the centre before narrowing inwards at each end.

This construction offers similar advantages to those described above forthe embodiment described with reference to FIGS. 56a-b, 57a-b 58a-b, and59a-b . That is, it assists with minimising the pressure drop as gasespass through the pillows portion. The other advantages as outlined abovealso apply. However, the variation in the design also has the advantagethat the strength and flexibility is improved.

For the embodiments described above with reference to FIGS. 56-60, it ispreferred that the wall thickness of the base section is substantiallyconstant over the height of said base section air path through the basesection is substantially defined by the contours of the walls of saidbase section.

A variation of the embodiments described above in relation to FIGS.56-60 of the nasal pillow portions is shown in FIGS. 61a and 61 b.

The nasal pillow portion of FIGS. 56a to 56c is shown in cross-sectionin FIG. 61b . The cross-section lines X and Y are shown in FIG. 61b . Inthis variation, four ribs are equally spaced around the perimeter of thepillow portion, extending inwards from the wall of the pillow portiontowards the centre of the pillow portion generally radially.

In the preferred embodiment shown in FIGS. 61a and b , the ribs extendfrom the bottom of the base section, upwards to a point just above thebottom of the cap. The inner edge or surface of the rib or ribs curvesinwards—that is, it curves towards the central axis of the pillowportion. As can be seen in FIG. 61b , the nozzle or opening at the topof the cap has a certain width, and it is preferred that the ribs do notextend inwards from the walls far enough to overlap with the edges ofthis. That is, the maximum size of the ribs would be on or before thisinterference point. The edge or perimeter of this interference pointwould be the perimeter of a circle defined by looking straight down theaxis of the pillow portion from the top opening of the cap from above.That is, the maximum inwards extent of the rib or ribs is the perimeterof a circle defined by looking straight down the axis of the pillowportion from the top opening of the cap from above.

The ribs 6101 are preferably thicker than the wall of the pillowportion. More preferably the ribs 6101 are twice the thickness of thepillow portion wall. As an alternative the ribs 6101 may be thinner thanthe pillow portion wall. The ribs 6101 are preferably all substantiallyidentical to each other in terms of dimensions and shape. However theribs 6101 may vary from each other in thickness, width, length andheight. The ribs 6101 are preferably arranged at equal intervals aroundthe perimeter of the pillow portion. Alternatively the ribs 6101 may bearranged at irregular intervals.

The addition of the ribs 6101 offers the same advantages as describedpreviously for fifty second to fifty sixth embodiments. The addition ofthe ribs 6101 strengthens and stiffens the base section and cap of thepillow portion. The ribs 6101 help to prevent the base section fromdeforming or folding when the pillow portions are being fitted or whilein use, by acting as a strengthening member to stiffen or strengthen thebase section. The ribs also act to support and strengthen the cap fromdeforming and collapsing into the airway or blocking the orifice. Thisensures the airway is unblocked and reduces the pressure drop across thepillow portions, making it easier for a user to breathe through thepillow portions.

A variation of this arrangement is shown in FIGS. 62a and 62b . In thisvariation, instead of the inner surface or edge of the ribs beingrounded inwards towards the centre axis of the pillow section, the innersurface or edge follows a straighter line between the bottom of the basesection and a point just above the bottom of the cap. The inner surfaceor edge of the rib or ribs can be substantially straight or evenslightly curved outwards towards the inner wall of the pillow portion.

A further embodiment of the nasal pillow portions is shown in FIGS. 63a,63b and 63 c.

In this variation a pair of pillows portions 6350-1, similar to thosedescribed above with reference to FIGS. 56a-c is shown being used with agasket portion 550-2.

The base portions 6350-1 a are substantially the same as the baseportions 5650-1 a described with reference to FIGS. 56a-c . The capsconnected at each upper end of the base portions are different asdescribed below.

The cap 6350-1 b is substantially flexible and supple and capable ofdeforming and flexing to fit the nostrils of a user to create a seal.The cap 6350-1 b is shaped to guide gases into a patient's nostrils withcurved or sloping walls that narrow to an exit orifice 6310. Mostpreferably the cap 6350-1 b is shaped substantially like a bottle neckas seen in FIG. 63c . The base portion 6350-1 a and cap 6350-1 b definean airway or hollow pathway that passes through the pillow portion toallow gases flowing from the gasket 550-2 to exit through the orifice6310. It can be seen from FIG. 63a that there is an intermediate portion6301 which extends upwards from the base portion 6350-1 a, with theperimeter of the bottom of the intermediate portion 6301 generallycongruent with the perimeter of the upper part of the base portion. Thebottom of the cap, which is the widest part of the cap, fits inside theintermediate portion so that the intermediate portion generally forms arampart, parapet or boundary wall around the top of the base portion,with the bottom of the cap inside this boundary wall.

The boundary wall formed by the intermediate portion 6301 acts to form asecondary seal with the users nostrils once the caps 6350-1 b are fittedinto the nostrils of the user. The intermediate portion 6301 abutsagainst the outside of the nose to form a seal. The border of thissecondary seal is shown in FIGS. 65a and 65b as the dotted line B.

It should be noted that the three separate parts forming the pillowportion (the base portion, the intermediate portion and the cap) are inthe preferred embodiment formed as one single piece—they are not formedseparately and then connected together.

A variation to the nasal pillow portions shown in FIGS. 63a, 63b and 63cis shown in FIGS. 64a, 64b and 64c , and the specific structuraldifference are described in detail below.

The rampart, parapet or boundary wall formed by the intermediate portion6401 of the base portion 6401 of FIGS. 64a and 64b is constructeddifferently to the intermediate portion 6301 as shown in FIGS. 63a and63b and described above. The intermediate portion 6401 and the baseportion and cap are generally similar, but in the embodiment shown inFIGS. 64a and 64b , the intermediate portion is substantially flexibleand soft and deforms when it abuts against the nostrils of a user. Thedeformation assists with allowing the intermediate portion 6401 toconform to the shape of a user's nose and form a secondary seal. Thedeformation increases the effective area of the edge, as shown by dottedline C in FIG. 65b . This increase in the effective area assists in thecreation of a larger secondary seal.

A further embodiment of a nasal pillow portion is shown in FIGS. 66a and66 b.

The nasal pillow portion shown in FIGS. 66a and 66b can be used withpillow gasket 250-2 (not shown), or alternatively with a differentpillow gasket such as for example pillow gasket 350-2 or 450-2, asdescribed above.

The nasal pillow portion 6600 of this embodiment consists of two mainparts—a stalk 6650-3 and a cap 6650-1. The pillow portion is connectedto the pillow gasket at the base or lower end of the stalk.

The cap 6650-1 of this embodiment is connected to the top of the stalk6650-3. The stalk forms a gases path so that gases can pass from thepillow gasket through the stalk into the cap, the gases exiting the capthrough an aperture 6610 at the top of the cap. Internally, the cap6650-1 has an enlarged cavity 6603, which has a width slightly widerthan the width or diameter of the inside of the stalk—the diameter orwidth of the air passage.

The cap 6650-1 also has a flange portion 6601, which in the preferredembodiment is formed integrally with the cap, around the lower part ofthe cap, sloping downward and outward so that the upper part of thestalk is surrounded by the flange portion 6601, which forms anoverhanging ‘eve’, mantle or ledge. The flange portion 6601 issubstantially flexible. The pillow portion 6600 also has at least one,but more preferably a plurality of ribs 6602. Most preferably the pillowportion 6600 includes four ribs 6601. The ribs 6601 are locatedunderneath the flange portion and extend between the underside of theflange portion and the outer surface of the stalk. The ribs extend fromthe stalk 6650-3 to the edge of the flange portion 6601, as seen in FIG.66b . It is preferred that the lower edge or surface of said rib or ribsdoes not extend downwards further than the lower edge of said flange.Preferably the width of the ribs 6602 is greater than or equal to thethickness of the wall of the cap 6650-1. More preferably the width ofthe ribs 6602 is equal to the thickness of the cap 6650-1 wall.Preferably the ribs 6602 are identical to each other in shape anddimensions. Preferably the ribs 6602 are spaced apart at equal intervalsto each other around the stalk, extending radially outward. In thepreferred embodiment, as shown in FIG. 66a , two ribs are locatedtowards one side of the cap 6650-1 and the other two ribs are located atthe opposite end, as shown in FIG. 66 a.

The purpose of the ribs 6602 is to hold the flange away from the stalkin use. The ribs 6602 act to support the flange against loads exertedupon the flange portion 6601. The flange portion 6601 generally deformsor folds while the cap 6650-1 is being fitted into a user's nostrils. Ifthere is too much folding or deforming, the seal can become ineffective.The flange portion 6601 folding can also cause the flange portion 6601to bear on the stalk 6650-3 and may lead to the stalk 6650-3 pinchinginward and constricting the airway 6640. Surprisingly it has been foundthat the addition of the ribs to the flange portion 6601 localisesmovement of the cap 6650-1 to the upper areas of the cap 6650-1. Theupper part of the cap 6650-1 flexes and deforms in order to conform tothe shape of a user's nostrils. This leads to reduced movement of theflange portion 6601 and stalk 6650-3 resulting in a minimising of theleak of gases around the opening of the nostrils. The flange portions6601 help to create a more effective seal with the user's nostrils.

A further embodiment of the nasal pillow portion is shown in FIGS. 67aand 67b . The embodiment shown in FIGS. 67a and 67b is substantially thesame as that described above in relation to FIGS. 66a and 66b above,with specific structural differences as outlined below.

For the embodiment described in relation to FIGS. 66a and 66b , theinternal cavity 6603 or enlarged cavity 6603 is described as beingslightly wider than the internal width or diameter of the stalk. In theembodiment shown in FIGS. 67a and 67b , the internal walls of the pillowportion which form the gases path between the base of the stalk and theaperture 6710 are straight-sided or parallel, or possibly slightlytapered towards on another from the bottom to the top. The aim of thisstraight-sided or tapered arrangement is to reduce the pressure dropacross the interface.

3.16 Lexicon

‘Supple’ or ‘flexible’ as these words are used in this specificationwith reference to the nasal pillows or pillow portions should be takento mean that the item can be substantially and repeatedly deformed, forexample, by a user pinching, squashing or crushing it in their hand,with the item returning to its original shape with little to no plasticdeformation occurring. An item having a rectangular or squarecross-section, with a thickness of 1-2 mm, a width of e.g. 1 cm, and alength of 5 cm or more, formed from a ‘supple’ or ‘flexible’ material asit should be understood in this specification, will, if held at one end,bend to an extent easily appreciable to the naked eye—i.e. it will bendat least 2-3 mm. The most preferred materials having ‘supple’ or‘flexible’ properties as they should be understood within the context ofthis specification will, if formed in the manner referred to above, bendcompletely—that is, bending enough so that the unsupported end pointssubstantially directly downwards. If the material does not bend to anappreciable extent, then it is a rigid or semi-rigid material for thepurposes of this specification—see below. It should also be understoodthat ‘flexible’ is intended to mean a material that is soft, supple andflexible enough that an item formed with the dimensions outlined above(1-2 mm×10 mm×50 mm) could be rolled into a solid tube (i.e. with nocentral ‘hollow’ portion), and when the tube is unrolled there would belittle to no plastic deformation of the material.

‘Rigid’ or ‘semi-rigid’ as it is used in this specification should beunderstood to mean that an item described in this manner can beelastically deformed, but that it would require application of anexternal force apart from gravity (i.e. more than its own weight) to doso—a ‘rigid’ or ‘semi-rigid’ item will not collapse or bend under itsown weight, in any orientation. It is noted that all items usuallydescribed as rigid do have a certain degree of elasticity, but theelastic limit will normally be reached before the elastic deformation ofthe rigid material is appreciable to the naked eye. Glass, for example,will shatter before the average person is able to appreciate that it haselastically deformed at all. An item having rectangular or squarecross-section, with a thickness of 1-2 mm and a length of up to 10 cm,formed from a ‘rigid’ or ‘semi-rigid’ material as it should beunderstood in this specification, will not bend to an extent easilyappreciable to the naked eye. As an example, the arms of the Fisher &Paykel Opus™ interface or the ResMed Mirage Swift™ II interface arearound 10-11 cm long and have a thickness of less than 1 mm. The arms ofthese devices are formed from a plastic having a rigidity so that theywill not bend under their own weight if held at one end, and for thepurposes of this specification can be considered to be ‘rigid’ orsemi-rigid’.

‘Substantially vertically downwards’ as it is written in thisspecification should be interpreted as not necessarily meaningabsolutely vertical—an angle of 10-20 degrees or more off-vertical lieswithin the meaning of ‘substantially vertical’ as it is used in thisspecification.

It should also be noted that ‘downwards’, ‘outwards’, ‘inner’, ‘outer’,‘rear’, ‘front’, and similar terms as they are used in thisspecification refer to the mask being worn by a user who is standing up.For example, ‘inner’ and ‘rear’ refer to that side of the interfacenearest a users face in use. However, in use the interface is intendedto be used by a user who is asleep and will be lying on a bed, either ontheir back, front or side. The convention referred to above (a userstanding) has been adopted for ease of reference.

It should also be noted that the term ‘interface’ or ‘interfaceassembly’ as it is used in this specification refers to any combinationof the interface core section 11, 311 or 411, the interface conduit 19,and the headgear assembly 12—that is, for the preferred embodiment, theterm ‘interface’ could refer to the interface core section 11 with orwithout the headgear 14, and with or without the supply conduit 19.

The terms ‘swivel’ and ‘rotate’ have their normal dictionarydefinitions. However, it should specifically be noted that as used inthis specification, ‘rotate’ means that the item turns around an axis orcentre point and movement is in a single plane. In contrast, ‘swivel’ asused in this specification should be taken to mean that the item iscapable of movement in more than one plane.

The thickness of the wall of either the inner cap or outer cap is thecross sectional thickness, meaning the thickness of the wall when viewedin cross section.

The thickness of the bead or any other feature refers to the crosssectional thickness, meaning the thickness of the bead when viewed incross section, unless otherwise stated.

The term tri-type shape describes a generally triangular type shape. Itis the shape formed from the lines joining each vertex point of atriangle to the centre.

The term user and patient can be interchangeably used in thisspecification. They both have the same meaning in terms of thespecification.

4. Ribbed Nasal Pillows

Nasal interfaces with reference to FIGS. 68 to 75 will now be described.

4.1 Headgear

FIG. 68 and FIG. 69 show a preferred embodiment of a nasal interface6850, comprising a headgear 6821 and nasal cannula assembly 6802. Theheadgear 6821 is worn by the user in use, and holds the nasal cannulaassembly 6802 in the required position. The headgear 6821 in thepreferred form is comprised of headgear straps 6835, 6836, 6837, 6838,and two arms 6833, 6834 which are connected on each side of the nasalcannula assembly 6802. The two arms and manifold are substantiallyrigid, or at least more rigid than the headgear straps.

It should be noted that many equivalent forms of headgear known in theart may be suitable for use with the nasal cannula assembly 6802 of thepresent invention. What has been described above is the preferred formfor use with the nasal cannula assembly 6802 of FIGS. 68 to 75.

4.2 Nasal Cannula Assembly

The nasal cannula assembly 6802 of the preferred embodiment of theinvention shall now be described in detail with reference to FIG. 68,and FIGS. 70a and 70b . The nasal cannula assembly 6802 is comprised ofa manifold 6822 and a pair of nasal pillows 6840.

The manifold 6822 is preferably made from a substantially hard (rigid)plastics material, such as polypropylene, polycarbonate or acetyl, orother similar rigid materials. Alternatively, the manifold may be madefrom a semi-rigid material such as a thermoplastic elastomer, siliconerubber or urethane, or other similar semi-rigid material.

In use, the manifold 6822 is located adjacent the patient's nose, belowthe nose and in front of the patient's philtrum.

The two arms 6833, 6834 of the headgear are attached to the manifold6822 in use. In the preferred form they are integrally moulded with themanifold 6822, one arm being moulded to a first end of the manifold, andthe second arm being moulded to a second end of the manifold.

Alternatively, the two arms may be connected to form a continuouselongate member, the elongate member being attached to the manifold. Theelongate member may be attached to a front surface of the manifold,passing across the front of the manifold. Alternatively the elongatemember may be attached to any other surface of the manifold, for examplepassing underneath the manifold.

When a user is wearing the nasal interface 6850, the load of the nasalcannula assembly is transferred away from the user's nose and onto thecheek regions of the user.

The manifold 6822 has an inlet 6828 which in use receives a flow ofrespiratory gases from the gases conduit 6803. In the preferredembodiment, the inlet 6828 comprises a semi-tubular projection from themain body of the manifold 6822, which in the preferred form is adaptedto receive joint end 6861 of a connector 6860 in use. In the preferredembodiment, the connector 6860 is an L-shaped tube, with end 6861 shapedas a ball joint. The projection 6828 forms a socket for the end 6861 ofthe connector 6860 and in use the connector 6860 can swivel within thesocket. The other end of the connector 61 is attached to gases conduit6803 to allow for gases to be passed into the manifold 6822.

In alternative embodiments, the manifold 6822 may not include projection6828 and the inner surface of the manifold 6822 may be curved and form asocket for receiving the connector joint end 6861. In other alternativeforms, other types of connection may be utilised between the manifold6822 and the connector 6860, such as a flexible piece of silicone, orother appropriate connection mechanism.

The flexible joints described above allow the conduit 6803 to swivel andmove relative to the manifold 6822. In this manner, small movements ofthe connected conduit 6803 and the headgear 6821 can be absorbed withoutmovement of the nasal pillows 6840 in the nostrils or nares of thepatient 6801. In the preferred form, the body of the conduit 6803slightly upstream of the nasal cannula assembly 6802 may be attached toany of the headgear straps in order to hold it out of the way.

It should be noted that the connection between the manifold 6822 and theconduit 6803 as described above allows the conduit to be flexed orrotated to allow for minor ‘in use’ movements of the conduit withoutcausing the dislodgement of the nasal pillows 6840 of the nasal cannulaassembly 6802 from the user's nares. However, this is not an essentialpart of the invention, it is a preferred variant.

4.3 Nasal Pillows

The nasal cannula assembly 6802 of the present invention includes twonasal pillows 40, which are shown connected to the manifold 6822 in FIG.74, and which are shown in exploded view in FIGS. 70a and 70b . A singlenasal pillow 6840 is shown in FIG. 71. Each of the nasal pillows 6840 isfrustoconical in shape and in use rests against the patient's nostrils,to substantially seal against the patient's nostrils.

Each nasal pillow 6840 is composed of two main parts: a stem or tubularbase 6841 and a nasal puff 6849. The nasal puff 6849 is supported on theintegral tubular base 6841. The tubular base 6841 and nasal pillow 6840are preferably integrally moulded as a one piece item from asubstantially flexible plastics material. In the preferred form thismaterial is silicone, but other appropriate materials, such as rubber ora thermoset elastomer or thermoplastic elastomer such as Kraton™ may beused.

The preferred form of manifold 6822 includes two holes 6823 side by sidein the top of the manifold 6822. In use, the bottom end of each tubularbase 6841 fits into each of the holes 6823. It is preferred that thetubular base 6841 has a circumferential groove 6842 running around thebase 6841 near the bottom end. The circumferential groove 6842 providesa channel. An edge portion 6824 of the manifold hole 6823 fits withinthe groove 6842 to hold the nasal pillow 6840 in position on themanifold 6822 in use. The diameter of the circumferential groove may beslightly larger than the diameter of the hole, so that when installed,the flexible material of the tubular base is slightly compressed. Wheninstalled in the hole, the tubular base 6841 is firmly retained due tofriction between the edge of the manifold hole 6823 and the base of thegroove 6842.

Alternatively, the diameter of the circumferential groove may beslightly larger than the diameter of the manifold hole. In this case thecircumferential grove width may be slightly thinner than the thicknessof the manifold edge portion 6824. When installed into the manifoldhole, the pillow tubular base 6841 is firmly retained by frictionbetween the edge portion of the hole 6823 and the sides of the groove6842.

Alternatively, the diameter of the circumferential grove and the widthof the circumferential groove may be sized to provide a relatively loosefit between the tubular base and the manifold hole.

The manifold holes 6823 and the tubular base 6841 of each of the nasalpillows 40 may be round, or alternatively they may be substantiallyelliptical in shape. Preferably the holes 6823 and tubular bases 6841are substantially elliptical. This allows only two orientations of fitbetween the tubular base 6841 and the manifold hole 6823. Due to theshape of the nasal pillows 6840 and with only two orientations of fitpossible, when fitting the tubular base 6841 to the manifold 6822, thecorrect orientation between the tubular base 6841 and hole 6823 will beobvious to a user.

Alternatively, the bottom end of the tubular base 6841 and correspondingmanifold hole 6823 could be mutually shaped to provide a single possibleorientation for fitting, so that the user cannot fit the nasal pillow6840 to the manifold 6822 incorrectly.

Alternatively, to ensure correct orientation between the hole 6823 andtubular base 6841, the tubular base may incorporate a key or keyway,with the manifold hole 6823 incorporating a corresponding keyway or key.For example, the groove 6842 may not pass around the entirecircumference of the tubular base so that a tab 6843 is formed betweeneach end of the groove 6842. A corresponding notch 6825 in the edge ofthe manifold hole 6823 ensures correct alignment. Any such key andkeyway arrangement known to a person skilled in the art may be used toensure correct alignment between the nasal pillow 6840 and the manifold6822.

Additionally, each tubular base 6841 may be shaped or keyed, or both, sothat it may be fitted to only one manifold hole 6823. This arrangementensures the left hand nasal pillow can only be fitted to the left handmanifold hole, and the right hand pillow to the right hand manifoldhole.

Alternatively, the tubular bases 6841 of the nasal pillows 6840 may beover moulded onto a substantially rigid tubular material, shaped andsized to conform to the shape and size of the manifold 6822. In thisalternative embodiment, the interface between each of the tubular bases6841 and the manifold 6822 is between the rigid material of the nasalpillow base and the rigid material of the manifold. For thisarrangement, a snap or bump type fitting, or a clip type fitting may beincorporated to cause fitting between the nasal pillows 6840 and themanifold 6822.

Alternatively, the manifold 6822 may incorporate two tubular projections6826 (shown in FIG. 70b ) that extend from an upper surface of themanifold 6822. When assembling each of the nasal pillows 6840 to themanifold 6822, the tubular base 41 of each pillow 6840 may fit over acorresponding tubular projection 6826 extending from the manifold 6822.Each pillow 6840 is maintained on a corresponding tube 6826 by frictionfit. Other types of fitting may be provided for, such as a snap or bumpfitted part, or the tubular pillow base 6841 may be over moulded to aclip that is fitted to the manifold 6822. To assist with a friction fit,the internal diameter of the tubular base 6841 may be slightly smallerthat the outer diameter of the tubular projection 6826, so that thepillow base 6841 must be slightly stretched over the tubular projectionin order to hold it in place. Alternatively, the tubular projections6826 and the tubular bases 6841 can be sized so that the ends of thebases 6841 fit inside the projections 6826.

The interface between the tubular projection 6826 and the tubular base6841 may incorporate a key and keyway to ensure correct orientation ofthe nasal pillow to the manifold 6822. A projection 6827 on the manifoldtubular projection 6826 allows for correct fitting or keying of thenasal pillow 6840 to the manifold 6822, such that when the tubularpillow base is fitted onto the manifold tube, the projection 6827 entersa corresponding recess 6844 formed in the nasal pillow tubular base6841. Alternatively, a recess may be provided in the outer surface ofthe manifold tube, and a corresponding projection provided on theinternal surface of the pillow tubular base 6841.

For the embodiments described above, the nasal cannula assembly 6802 ofthe present invention incorporates two nasal pillows 6840, each having aseparate base 6841, each base 6841 fitted individually to the manifold6822.

In an alternative embodiment, the two nasal pillows 6840 may beintegrated into a common base. In this alternative embodiment, thecommon base interfaces with the manifold in a similar way to that ofeach individual tubular base 41 of the embodiments described previously.

The nasal puff 6849 of the nasal pillow 6840 of the present inventionpreferably has the general overall form of an elliptical cone and assuch each nasal puff 6849 is tubular and allows gases to flow from theconduit 3, through the manifold 22 through the nasal pillows 6840 and tothe user 6801. The nasal puffs 6849 of the pillows 6840 include anoutlet 6845, which in the preferred embodiment is at the top of theelliptical cone, with the outlet 6845 preferably being elliptical aswell. When mounted on the manifold 6822, it is preferred that thepillows 6840 are angled toward one another and also that each of thepuff portions 6849 (or at least the outlets 6845) are slightly offsetfrom the centre of each pillow 6840 as shown in FIG. 5.

FIGS. 72 and 73 a show the offset outlet 6845 of the preferred form ofnasal pillow in more detail. Viewed from above, the pillow 6840 has anouter profile 7300 and the outlet 6845 has an inner profile 7301 withrespective centre points 7302, 7303. The inner profile 7301 (formed bythe outlet 6845 of the nasal pillow 6840) is offset inward, by ahorizontal spacing 7304 and vertical spacing 7305. This means that theoutlet 6845 of the nasal pillow 6840 is offset horizontally by thedistance shown as horizontal spacing 7304 towards the middle of thenose, and vertically by the distance shown as vertical spacing 7305towards the user's upper lip. Offsetting the outlet profile 7301 in thismanner allows the nasal puff 6849 and the outlet 6845 to be insertedinto a user's nostril without the outer profile 7300 pushing orimpacting on the user's upper lip. Offsetting the inner profile 7301inwards allows the nasal puff 6849 of the pillow 6840 to better seal onthe septum of the user's nose in use.

The outlet profile 7301 of outlet 6845 may also be angled compared tothe outer profile 7300 of the pillow 6840. For example in FIG. 72, thereis a horizontal angle difference between the outer profile 7300 andinner profile 7301. This difference is shown as horizontal angledifference 7306. A similar vertical angle difference between the outerprofile 7300 and inner profile 7301 is shown as vertical angledifference 7307.

As outlined above, the outer profile 7300 and inner profile 7301 havedifferent sections or offsets. This allows the gradient of theconnecting surface between the profiles to be changeable. This is shownin the graphs of FIGS. 73b, 73c and 73d . The connecting surface betweenthe inner profile 7301 and outer profile 7300 can have a differentsurface profile as shown by gradients 7308, 7309, 7310. The differentsurface profiles 7308, 7309, 7310 of the connecting surface are possibledue to the offset difference 7311, 7312 (horizontal, vertical or angled)between the inner profile 7301 and outer profile 7300.

There may also be a difference in the rate of change of the gradient (asillustrated in the difference between 7308 and 7310). This allows easierinsertion of the nasal puff 6849 into a user's nostrils due to theincreased amount of ‘lead in’. This also allows improved sealing due tomore ergonomic contouring of the connecting surface which is in contactwith the user's nostril.

4.4 Parallel Tubular Bases

Some prior art nasal cannula interfaces have their tubular bases angledin towards the centre of the user's nose, with the nasal puffs mountedsubstantially perpendicularly to each corresponding tubular base. Thepuffs of the prior art cannulae are spaced closer together compared tothe manifold end of the tubular bases. It is normal for a user totighten the head gear of their particular interface to fit it correctlyand also to help create a pressure seal between the user's nostrils andthe nasal pillows. In prior art assemblies, as the headgear istightened, the pressure between each pillow and the nare of a userincreases. The puff is compressed downwards onto the tubular base, whichis also compressed downwards, substantially along the axis of the puffand tubular base. As the headgear is tightened in place on a user'shead, it can be seen that the distance between the pillows increases, aseach pillow is compressed downwards and substantially along the angledaxis of its respective tubular base. The distance between the nasalpillows increases because the pillow tubular bases are spaced furtherapart at the manifold end, compared to the distance between the tubularbases at the puff end. This configuration can result in a poor fit andtherefore poor seal between the user's nostrils and the nasal puffs.

The nasal interface of the present invention helps to overcome thisproblem by arranging the tubular bases of the two pillows substantiallyin parallel. This is shown in FIG. 74. Each tubular base 6841 extendssubstantially parallel from the manifold 7322, relative to a centre lineof the user's nose. To accommodate the typically angled nostrils andbase of a user's nose and create a good seal, each puff 6849 isconnected to the upper end of the tubular base 6841 at an angle.

As the nasal puffs 6849 and tubular bases 6841 of the present inventionare compressed during fitting of the assembly 6802 to the user's nose,the puffs and tubular bases are compressed downwards and substantiallyalong parallel axes and therefore do not separate. It has been foundthat this configuration, with tubular bases 6841 arranged in parallel,with puffs 6849 integrated to the tubular bases 6841 at an angle,results in an improved seal between the puffs and the user's nostrils.The seal is less likely to be broken by a user over-tightening theheadgear straps, and is therefore more consistent.

In the preferred embodiment of the present invention, the puffs 6849 areintegrated to the top of the tubular bases 6841 at an angle of between10 and 30 degrees. Preferably, the puffs 6849 are integrated to the topof the tubular base at an angle of between 15 and 25 degrees. It hasbeen found that for the majority of users, the best seal is achievedwith a puff angle of substantially 20 degrees to the top of the tubularbase 6841.

4.5 Ribbed Tubular Bases

A further improvement has been achieved by adding a ribbed section 6848to each tubular base 6841. In the preferred form, the ribbed sectionextends around the circumferential perimeter of the tubular base 6841,between the nasal puff 6849 and close to the bottom end of the tubularbase 6841. Alternatively, the ribbed section may extend part way aroundthe circumferential perimeter of the tubular base. In the most preferredform, the ribbed section 6848 extends from the top of the tubular base6841, where the puff 6849 connects to the top of the tubular base 6841,to part way down the tubular base. The bottom of the ribbed section maybe at an angle to the axis of the tubular base, the angle beingsubstantially the same as the angle of the puff to the tubular base.Alternatively, the bottom of the ribbed section may be perpendicular tothe axis of the tubular base 6841. The ribbed section may also extendthe full length of the tubular base.

The ribbed section is formed from a plurality of adjacent parallel ribs6846, with the ribs 6846 in the most preferred form being parallel tothe longitudinal axis of the tubular base 6841. Each of the ribs 6846 isformed in the tubular base 6841 by having thick walled portions 6850parallel to the longitudinal axis of the tubular base, the thick walledportions being spaced apart at intervals around the circumference of thetubular base 6841. The thick walled portions 6850 are separated fromadjacent thick walled portions 6850 by intervening thin walled portions6847, the thin walled portions being parallel to the longitudinal axisof the tubular base (that is, around the perimeter or circumference ofthe base 6841, the thick-walled portions 6850 alternate with thethin-walled portions 6847. Each rib 6846 is made up of one thick wallportion 6850 with a thin wall portion 6847 on either side). In thepreferred form, the wall thickness (between the inside and the outsideof the tubular base) of the thick-walled portions 6850 is approximately1.5 mm, slightly thicker than the wall thickness of a nasal pillow knownin the art. The thin-walled sections 6847 are slightly thinner than thewall thickness of a nasal pillow known in the art, approximately 0.5 mm.

The thick walled portions 6850 and the thin walled portions 6847 may beformed substantially rectangular in cross section. As shown in FIG. 75a, the ribbed section 6848 of the tubular base 6841 may be formed withthe outer surface of the ribbed section 6848 of the tubular base 6841substantially smooth, with a resulting square-wave type ribbed profilein the inner surface of the ribbed section 6848 of the tubular base6841. Alternatively, as shown in FIG. 75b , the ribbed section 6848 ofthe tubular base 6841 may be formed with the inner surface of the ribbedsection 6848 of the tubular base 6841 substantially smooth, with aresulting square-wave type ribbed profile in the outer surface of theribbed section 6848 of the tubular base 6841. Or, alternatively a centreline of the thick wall portions 6850 and a centre line of the thin wallportions 6847 may be aligned or offset so that a square-wave type ribbedprofile results in both the inner and outer surfaces of the ribbedsection 6848 of the tubular base 6841, as shown in FIG. 75 c.

Furthermore, the thick-walled portions 6850 may have a rounded form, orthe thin walled portions 6847 may have a rounded form, or both the thickwalled portions 6850 and thin walled portions 6847 may have roundedforms. A wave type ribbed profile may result in the inner surface of theribbed section 6848 of the tubular base 6841, with a smooth outersurface of the ribbed section 6848 of the tubular base 6841, as shown inFIG. 75d . Or, a wave type ribbed profile may result in the outersurface of the ribbed section 6848 of the tubular base 6841, with asmooth inner surface of the ribbed section 6848 of the tubular base6841, as shown in FIG. 75e . Alternatively, the thick walled portions6850 and thin walled portions 6847 may be arranged so that a wave typeribbed profile results in both the inner and outer surfaces of theribbed section 6848 of the tubular base 6841, as shown in FIG. 75 f.

Alternatively, the ribs could for example be formed by adjoiningcylindrical sections, as shown in FIG. 75g . The thick wall sectionwould be the largest distance (usually the diameter) from the innersurface to the outer surface of the ribbed section 6848 of the base6841, with the thin wall section being the point at which adjacent onesof the cylindrical sections are touching or connected, the shortestdistance from the inside to the outside of the ribbed section 6848 ofthe base 6841.

The cross-section of the tubular base of the present invention with thinportions 6847 and thick portions 6850 is substantially similar to thecross-section of the tubular base of prior art nasal pillows withoutribs. This means that the tubular bases 6841 of the present inventionare able to resist similar compressive loads to a prior art pillow base,in a similar manner. To create a good seal between the puffs 6849 andthe user's nostrils, it is important for the nasal puffs 6849 and thetubular bases 6841 to provide some compressive resistance to push thepuffs 6849 against the user's nostrils as the headgear is tightened ontothe user's head. The thick portions 6850 substantially parallel to thelongitudinal axis of the tubular base 6841 provide the longitudinalsupport in the pillows necessary for achieving a good seal with theuser's nostrils.

The longitudinal thin portions 6847 allow the tubular bases to twistaxially more easily compared to prior art (unribbed) nasal pillows. Thethin sections 6847 create a ‘laminated’ type construction for thetubular bases 6841, allowing the thick walled portions 6850 to moverelative to each other more easily compared to a tube with uniformcross-section, so that axial twisting occurs more easily. It has beenfound that twisting of the pillows 6840 onto the user's nostrils occursas the cannula assembly 6802 is fitted to the user. Allowing thistwisting action to occur more easily helps to seat the puffs 6849 ontothe user's nostrils and create a good seal.

Also, the ribs and thin intervening portions allow the pillow bases tobe more easily deflected sideways, perpendicular to the tubular basesaxis, compared to the prior art nasal pillows. This side ways deflectionallows for varying nose shapes while still providing a seal between thenasal puff and the user's nostril.

It should be noted that although ribs parallel to the longitudinal axisof the tubular base have been described above, the rib sections may alsobe angled or spiralled around the base 6841.

It has been found that an improved seal is achieved with the nasalpillows 6840 of the present invention. The parallel tubular bases 6841help to maintain a constant distance between each pair of nasal pillows6840 as the nasal assembly 6802 is fitted to the user's head. The ribbedsection 6848 in each tubular base 6841 allows each pillow to twist intoplace on each nostril to create a good seal.

In the preferred form, a range of nasal pillows 6840 of variousdifferent sizes is available, such that a user may remove a pair ofexisting nasal pillows 6840 from the manifold 6822, and simply attach adifferent sized pair of pillows 6840 to the manifold 6822.

5. Nasal Interface with Silicone Side Arms (Nano)

FIG. 76 shows a perspective view from the front and to the side of thepreferred embodiment of an interface assembly 7601, showing an interfacecore portion 7602 or interface core section 7602, with a headgearassembly 7603 and a supply conduit 7604 connected to the interface coreportion 7602. A lanyard 7605 is connected to the supply conduit 7604,with the interface 7601 ready for use by a patient or user. Theinterface core section 7602, headgear assembly 7603, supply conduit 7604and lanyard 7605 which make up the preferred form of interface 1, andtheir inter-relationship, will now be described.

5.1 Interface Core Section

The interface core section 7602 includes a main body section that formsa manifold 7608. The manifold 7608 includes an inlet or gases supplyaperture 7609 which is adapted for releasable connection to the gasessupply conduit 7604. That is, the gases supply aperture 7609 and thegases supply conduit 7604 are mutually adapted to releasably connecttogether in use. How this connection is formed for the preferredembodiment will be described in further detail below. In the mostpreferred embodiment, the gases inlet or supply aperture 7609 is locatedat the front of the manifold 7608, and in use (i.e. with a user wearingthe interface and standing up) the supply aperture 7609 is alignedsubstantially vertically downwards. In variations of this most preferredform, the gases inlet 7609 may be angled forwards as well assubstantially downwards. ‘Substantially vertically downwards’ as it iswritten in this specification should be interpreted as not meaningabsolutely vertical—an angle of 10-20 degrees or more off-vertical lieswithin the meaning of ‘substantially vertical’ as it is used in thisspecification. In use, gases from the supply conduit 7604 enter themanifold 7608 via the gases supply aperture 7609. In the most preferredfrom, the aperture 7609 is located at the outer end of a short length oftube which forms part of the manifold 7608, the aperture 7609 being ovalin cross-section (viewed along the longitudinal axis of the short lengthof tube). In the preferred form, the manifold 7608 (including the gasessupply aperture 7609) is formed from a rigid or semi-rigid plastic.Examples of a suitable rigid or semi-rigid material would be apolycarbonate plastic, a polypropylene plastic or similar. The manifold7608 can be formed from e.g. a plastic that is similar to that used inthe frame or side arms of the Fisher & Paykel Opus™ interface or theResMed Mirage Swift™ II interface. Examples of what is meant in thisspecification by the terms ‘rigid’ or ‘semi-rigid’ are included in the‘Lexicon’ section below.

The most preferred form of manifold 7608 includes a limited flow outlet7610 for providing gas washout from the interface 7601. The preferredform of outlet 7610 is a collection or group of small apertures in themanifold 7608, in the preferred form located on the manifold 7608 sothat they are close to the connection with the supply conduit 7604, thatis close to the gases supply aperture 7609, and on the top of themanifold 7608 in use.

A pair of nasal pillows 7611 are connected to the manifold 7608 by wayof a gasket 7636. The nasal pillows 7611 and the gasket 7636 arefluidically connected to the manifold 7608 in such a manner that astream of gases entering the manifold 7608 through the gases supplyaperture 7609 passes through the manifold 7608 and enters the nasalpillows 7611. The gases stream enters at the bases of the pillows wherethey are fluidically connected to the manifold 7608, passes through thenasal pillows 7611, and exits at the open ends 7612 which in use arelocated in the nostrils of a user. Each of the nasal pillows 7611 isgenerally mushroom-shaped, having a stem 7613 and a cap 7614, the lowerend of the stem 7613 fluidically connected to the gasket 7636, which isfluidically connected to the manifold 7608. The open end 7612 is locatedat the top of the cap 7614. The outer surface of the cap 7614substantially seals against a users nares in use. ‘Substantially seals’as it is used in this specification should be taken to mean thatperfectly sealing against the nares with no leaks is the most desirableoutcome. However, a small degree of leakage around the sides of the cap7614 in use is almost certainly inevitable, and a person skilled in theart will understand that the phrase ‘substantially sealing’ is intendedto indicate that a very small amount of leakage may sometimes, but notalways, occur. As the nasal pillows 7611 are substantially sealedagainst the nares of a user, all or substantially all of the stream ofgases which passes through the manifold 768 and the nasal pillows 7611will be delivered to a user.

In order to aid in sealing the nasal pillows 7611 against the nares of awide variety of users, each of whom will have differently shaped andsized nostrils, the pillows 7611 are in the preferred form formed from asoft and supple material with a high degree of flexibility, such assilicone or similar.

5.2 Connecting or Supporting Arms

The interface also includes a pair of connecting arms 7615 a, 7616 a,extending one from each of the sides of the core section 7602. Theconnecting arms 7615 a, 7616 a connect the headgear assembly 7603 to thecore section 7602 in use. In the preferred embodiment, the connectingarms are attached to the core section 7602 so that they are angledslightly backwards, towards the face of a user in use, and slightlyupwards. Each of the arms has a generally rectangular cross-section, isbetween 1 and 2 mm thick, around 10 and 11 cm in length and has a widthof around 15 mm. In plan, the arms are generally rectangular, but tapertowards their outer ends.

In the preferred embodiment, each of the arms 7615 a, 7616 a is formedfrom a supple and flexible material which has the same or very similarproperties to the nasal pillows 7611, that is, the arms 7615 a, 7616 acan be crushed into a ball in the hand of a user, flexed so that theirends meet, etc, and once this external deforming force is removed, theywill return to their original shape with little to no plasticdeformation occurring. The material is soft, supple and flexible enoughthat each of the arms could be rolled into a tube, starting at e.g. theouter end, with little or no central hollow portion in the tube, andwhen unrolled there would be little to no plastic deformation of thematerial.

In the most preferred form, the supple and flexible material from whichthe nasal pillows 7611 and the connecting arms 7615 a, 7616 a is amaterial which has a hardness of between 10 and 60 on the shore A scale.In the most preferred form, the material used is a silicone material.

The ends of each of the connecting arms 7615 a, 7616 a are adapted toallow the attachment of the ends of corresponding arms on the ends ofthe headgear assembly 7603. In the preferred embodiment, each of theouter ends 7622, 7623 of the arms 7615 a, 7616 a includes a detachableelement 7630, 7631. In the preferred embodiment, the inner end of eachof the detachable elements 7630, 7631 is barbed or notched on each side,and the outer ends 7622, 7623 of the arms 7615 a, 7616 a include a loopon the outer surface of the arm. The inner end of each of the detachableelements 7630, 7631 is slipped through the loop in use so that the barbengages with the edge of the loop to hold the detachable element inplace on the arm. The outer ends of each of the detachable elements7630, 7631 include slots 7632, 7633 which are generally verticallyaligned in use.

In the most preferred form, the arms are formed so that in profile theyhave a bent or ‘L’ shape, shaped so that the bend generally follows therear corner of the manifold 7608. One face of the ‘L’-shape extendsgenerally outwards, from the rear of the interface core portion 7602towards the front, and is generally aligned with the top portion or faceof the gasket 76036 where the arm connects to or with the gasket 7636.The other face of the ‘L’ extends generally downwards along the rearportion of the interface core portion 7602. One face (the inner face) ofthe L-shape of each arm rests against the face of a user in use.

5.3 Headgear

The headgear assembly 7603 of the preferred form comprises at least onestrap 7620 which passes around the back of a users head in use, with theends 7624, 7625 of the strap 7620 connecting to the connecting arms 7615a, 7616. In the preferred form, the headgear assembly 7603 includes amain strap 7620 and a secondary upper strap 7621. In the preferred form,the ends 7624, 7625 of the main strap 7620 include two patches ofVelcro™ on the outer surface at each end—one ‘hook’ patch and one ‘loop’patch. When each of the ends 7624, 7625 is doubled back on itself toform a loop, the Velcro™ patches engage to hold this loop together. Inuse, the ends 7624, 7625 are passed one each through the slots 7632,7633 and then doubled back on themselves to engage the headgear assembly3 with the core section 7602.

The secondary upper strap 7621 is arranged so that it passes across thetop of a users head, with each end of the secondary strap 7621connecting to the main strap 7620 just behind the ears of a user.

One, or both, of the straps 7620, 7621 can include an adjuster such asbuckle 7640 shown in FIG. 77 for lengthening or shortening the strap7620 or strap 7621 if required. More than one buckle can be included oneach strap if required. These could be Velcro™ adjusters or buckles aspreferred. The headgear secondary upper strap 7621 could also beindependently formed and connected to the main strap 7620. Theadjustments could be at any location on the strap that is convenient,sides, front or rear. The straps could be of different widths orthicknesses as required for user comfort. For example, in the mostpreferred form, the main strap 7620 is wider than the secondary strap7621, and the main strap 7620 is wider at the front than it is aroundthe back of the users head.

Suitable strap materials may include a woven elastic strip or a narrowstrip of foam and fabric, such as Breathoprene™. Alternatively, theheadgear could be formed from silicone, or coated with silicone. Theheadgear arms could be padded or cushioned on their inside surfaces ifthey are formed from silicone, in order to increase user comfort.Padding could also be added to the preferred form of arms—those madefrom Breathoprene™ or similar.

5.4 Supply Conduit

In the preferred embodiment, the supply conduit 7604 is a flexible tubeformed from a plastic type material. The most preferred form of supplyconduit 7604 is approximately 30 cm or 1 foot in length, with anexternal diameter of between 1 and 2 cm and a thin ribbed wall, the ribsbeing approximately 2 to 3 mm thick and the wall between the ribs beingsignificantly less that 1 mm thick. However, it should be noted thatvariations from these dimensions are possible without departing from thescope of the invention, and also a non-ribbed conduit could be used ifrequired. It should further be noted that ‘flexible tube’ as it is usedin this specification should be taken to mean that the tube or conduitis flexible enough so that it is capable of being bent or deformedrepeatedly (for example, by bringing the two ends of the conduittogether, or by tying a loose knot in the conduit if it is long enough,e.g. approximately 30 cm or more in length), with the tube or conduitreturning to its original undeformed shape with little to no plasticdeformation occurring, every single time the tube or conduit is bent ordeformed in this manner.

In the most preferred form, the supply conduit 7604 will not support itsown weight when held at one end in such a manner that the main body ofthe conduit extends outwards from the held end generally horizontally.Over a 20 to 30 cm length of supply conduit (which has a diameter of 1to 2 cm and a wall thickness at the ribs of 1 to 3 mm and a wallthickness between the ribs of less than 1 mm), the unsupported end ofthe supply conduit will bend and ‘droop’ so that the unsupported endpoints substantially or directly downwards. Therefore, the supplyconduit bends through at least 70 degrees over this length. This is incontrast to the supply conduit used on for example the Opus™ nasal mask,where a supply conduit having substantially the same dimensions willonly bend by around 10 to 20 degrees over its length, and ‘droop’ byaround 2 to 3 cm.

The supply conduit 7604 has a first or distal end 7606 and a second, orproximal end 7607. In the preferred form, the second, or proximal end7607 is in use connected to the interface core portion 7602 by afriction push fit, a bayonet connection or similar, or by any othersuitable connection as might be known in the art. The gases supplyaperture 7609 and the proximal end 7607 are for example mutually formedas a male/female couple or similar. However, it should be noted thatthis connection could be made by way of a ball joint socket or similarto allow the flexible conduit and more specifically the proximal end7607 to be rotated through different angles and orientations relative tothe interface core portion 7602. This connection could also be made insuch a manner that the supply conduit 7604 and the manifold 7608 canswivel relative to one another.

The first or distal end 7606 is connected to a main CPAP delivery tubeor similar (not shown) so that when the preferred form of interface 7601is being used in the most preferred manner, the supply conduit 7604receives a stream of heated, humidified gases from a humidifier chamberor similar connected in line with a CPAP blower or similar, via the mainsupply conduit. This connection can be made in the same or a similarmanner to the connection described above for the gases supply aperture7609 and the proximal end 7607, or by any other suitable connection asmight be known in the art.

As outlined above, the most preferred form of manifold 7608 includes alimited flow outlet 7610 for providing gas washout from the interface7601, this being a collection or group of small apertures in themanifold 7608. However, in alternate forms, the gas washout or bias flowcould be by way of bias flow holes in the gases supply conduit 7604, ator close to the proximal end 7607. These could be a group or groups ofperforations in the gases supply conduit 7604.

5.5 Lanyard

In the most preferred form, a lanyard 7635 is connected at or close tothe distal end 7606 of the supply conduit 7604. In the most preferredform, the lanyard 7635 is a loop intended to be connected to the body ofthe user of the interface. For example, the lanyard 7635 may be wornaround the neck of the user, or it may be clipped to the users clothingor similar. The lanyard 7635 carries the weight of the main deliverytube allowing less pressure to be used to hold the interface in place.In the preferred form, the lanyard 7635 is configured so that it willpass around the back of a users neck so the weight is supported by theusers neck, with one point of the loop of the lanyard 7635 connected ator close to the distal end 7606 of the supply conduit 7604. In alternateforms, the lanyard could be formed as two separate lengths, with theinner or user ends of the lanyard 35 connected directly to the headgearas shown in FIG. 84c . In all the embodiments, that end of the lanyard7635 which is connected to the conduit 7604 could be connected in anyone of several ways which are known in the art. For example, by using ac-shaped clip which clips around either the conduit or a connectorattached to the end of the conduit, the c-clip being push-fitted intoplace. Alternatively, the end of the lanyard could be fitted with a hookand the conduit 7604 fitted with a corresponding loop or aperture on thesurface to engage with the hook. Alternatively, a drawcord could beused. Alternative forms of connection of the lanyard 7635 to the supplyconduit, and the lanyard to the headgear, are shown in FIGS. 84a to 84c.

The advantage of the flexible tube and lanyard is that the need forrigid headgear to support the load is removed, as the load from the CPAPtubing is not transferred to the mask body. This is due to a combinationof support from the lanyard 7635 and the fact that the supply conduit764 is significantly more flexible than a supply conduit of the typethat is used with the Fisher & Paykel Opus™ or the ResMed Mirage Swift™II nasal masks.

5.6 Combined Connecting Arms and Nasal Pillows

The most preferred form of interface 7601 will now be described withreference to FIGS. 78a and 78 b.

In the most preferred form, as described above, the interface 7601includes a rigid or semi-rigid manifold 7608. The centrally locatedgases supply aperture 7609 feeds into the central aperture or cavity ofthe manifold 7608. That part of the manifold 7608 which is furthest awayfrom the aperture 7609 and in use closest to a user is substantiallyopen or a substantially fully open face as best shown in FIG. 78b , theupper part or face of the manifold 7608 is open. It should be noted that‘upper’ in this specification refers to the ‘in use’ position with auser standing up.

The pair of nasal pillows 7611 are integrally formed with the basegasket 7636, the pillows and base gasket 7636 being formed from a suppleand flexible material as outlined above. The base gasket 7636 includesan open lower face or open lower portion 7637 which corresponds in useto the open upper face of the manifold 7608. In use, the perimeter ofthe open portion 7637 of the base gasket 7636 is stretched and pressedor passed over the outside of the open upper face of the manifold 7608so that it covers and closes the open face of the manifold 7608, withthe gasket 7636 sealing against the outer surface of the manifold 7608.It can be seen that all of the gases passing through the manifold 7608will pass into the gasket 7636 and the nasal pillows 7611. As can beseen in FIGS. 78a and 78b , the manifold 7608 in this form is tapered,flaring or expanding in a direction away from the inlet aperture 769,and towards the user. When the base gasket 7636 is stretched and placedinto position, it contracts back to an un-stretched state when it isover the manifold 7608, and the flaring of the manifold 768 helps tokeep the base gasket 7636 and pillows 7611 in position. The base gasket7636 will naturally be forced further on to the manifold 7608 as itcontracts. It should be noted that the gasket 7636 and connected pillows7611 and arms 7615 a, 7616 a can be attached and removed repeatedly fromthe rigid manifold 7608 as required by a user.

In this preferred embodiment, the support arms or connecting arms 7615a, 7616 a are formed integrally with the gasket 7636 and the nasalpillows 7611. The arms 7615 a, 7616 a, the base gasket 7636, and thenasal pillows 7611 are all formed as a one-piece item.

Surprisingly, the combination of a rigid manifold 7608 and soft orflexible gasket 7636 with soft and flexible arms 7615 a, 7616 a has beenfound to provide an interface which will remain in position, iscomfortable for a user, and which will allow the delivery of gases fortherapeutic purposes over sustained periods (e.g. an 8 hour sleep cycle)without coming loose, moving out of position, or becoming uncomfortablefor a user. No marks are left on the patients face after use due to softflexible nature of arms, and there is no need for the addition ofpadding to the inner surface of the arms to achieve this. Also, theinterface fits a wider range of patients face shapes due to softflexible nature of arms.

Even more surprisingly, it has been found that this can be achieved inthe most preferred form by moulding the gasket 7636, pillows 7611 andthe supporting arms 7615 a, 7616 a as a one-piece item, and thenconnecting this to a rigid manifold such as manifold 7608 which receivesgases. This also offers a manufacturing advantage as the core section7602 can be formed from two elements only, each of which are relativelysimple in shape (compared to those used to form the core section ofeither the Fisher & Paykel Opus™ or the ResMed Mirage Swift™ II nasalmasks. The surprising advantage is that there is less complexity for apatient when assembling or disassembling the interface as there arefewer parts. This also offers an advantage to the manufacturer as thereare fewer parts to manufacture. There is also a surprising efficiencyadvantage as there is a lower probability of leaks due to there beingfewer connecting joints in the system.

Even more surprisingly, it has been found that by using a rigid orsemi-rigid manifold and a supple or flexible gasket, pillows andsupporting arms, with the gases supply aperture arranged facingsubstantially vertically downwards when a user is wearing the manifoldand standing upright, the front-rear profile or dimensions can bedecreased to the point where the front-most features or portions of theinterface can in use be kept further back than the front tip orfront-most part of a typical or average users nose. This is shown inFIG. 81. This has proved to be surprisingly advantageous and beneficialfor users, as it allows a user greater freedom in choosing a preferredsleeping or ‘use’ position. Unlike prior art interfaces such as theFisher & Paykel Opus™ or the ResMed Mirage Swift™ II nasal masks, a usercan more easily sleep prone on their face or at least their frontwithout portions of the interface or associated elements such asheadgear being pressed into their face or head. The oval entry can alsobe used to achieve this surprising advantage either independently of, orin combination with, the downwards-facing aperture, as it helpsfacilitate this slim-line design, helping to ensure the interface doesnot protrude further out than end of nose and allowing more freedom ofsleeping position without dislodging the interface. As outlined above,this can help to facilitate a prone or stomach sleeping position.

It has also been found that the use of a core portion and supportingarms configured in the manner outlined above allows a user to morecomfortably sleep on their side. As the gases supply conduit 7604extends vertically downwards from the interface core portion 7602 (whena user is standing), they will not, if lying in bed, crush or squeeze asupply tube that feeds in or is connected to the side of the interface.

5.7 First Alternative Form

The first alternative form will now be described with reference to FIG.79.

The first alternative form is almost identical to the preferredembodiment described above when assembled. However, in this alternativeform, the soft, supple and flexible arms 7615 b, 7616 b are moulded orconnected directly on to the sides of the rigid manifold 7608. Thegasket 7636 b and the pillows 7611 are a one-piece item, and areattached to the manifold 7608 in a similar fashion to that outlinedabove in use, except that the gasket 7636 b includes slits or slots 7650at each side to allow the arms 7615 b, 7616 b to pass through so thatthe gasket 7636 b can seal against the outer surface of the manifold7608.

5.8 Second Alternative Form

The second alternative form shall now be described with reference toFIG. 80.

In the second alternative form, the gasket 7636 c and pillows 7611 arepermanently or integrally connected to the rigid manifold 7608, but thegasket 7636 c and pillows 7611 are still soft and flexible. The arms7615 c and 7616 c are formed as a unitary or one-piece item, merging attheir inner ends into a hollow aperture 7660 which is shaped and sizedwith the outer sides or surfaces of the gasket 7636. The gasket 7636 cis flared from the outer part towards the inner part (closest to auser), and the hollow aperture 7660 corresponds to this flaring, so thatwhen the manifold is passed into the hollow aperture 7660, that part ofthe manifold 7608 which forms the gases supply aperture 7609 and theouter part of the manifold 7608, including the limited flow outlet 7610,passes through the aperture 7660 and the inner part then wedges into thehollow aperture 7660. Any pulling force exerted on the inner ends of thearms 7615 c, 7616 c will cause the gasket 7636 c to become wedged intighter in the hollow aperture 7660. In this second alternative form, itis preferred that the thickness of the walls of the gasket 7636 c or thethickness of the walls of the hollow aperture 7660 are thick enough thatthe maximum anticipated force exerted on the inner ends of the arms 7615c, 7616 c in use will not cause either the aperture 7660 or the gasket7636 c to deform sufficiently to allow the gasket 7636 c to pass throughthe hollow aperture 7660.

Further Alternative Forms

In the most preferred form and the two alternative forms describedabove, the interface core section 7602 has a gases supply aperture 7609which is a male or female connector (male in the most preferred form)which connects by push-fit or similar to the gases supply conduit 7604,with the gases supply aperture extending downwards from the bottom ofthe interface core portion 7602.

In other alternative forms, this connection could be made e.g. by way ofa ball joint and socket, or any other suitable connection such as areknown in the art. It should also be noted that in alternative but lesspreferred forms, the gases supply aperture could be arranged so that itextends to one side of the interface. This would not provide theadvantages of the most preferred form or the two alternative forms asdescribed above, but would still allow a user to take advantage of thesoft, flexible and supple support arms. If the interface is configuredso that a gases supply conduit extends to the side or over the top of ausers head, the headgear can be fitted with a connector to clip orconnect the supply hose to the headgear.

5.10 Gasket

The preferred form of gasket 7636 shall now be described with particularreference to FIGS. 78a , 81 and 82 a.

In the most preferred form of gasket 7636, the gasket is shaped so thatthe two side portions are slightly angled towards one another. That is,the top surface which covers the open rear face of the manifold 7608appears to have a V-shape when viewed from the front, with the pillows7611 one on each of the two sub-surfaces or inner faces of the ‘V’. Theangle of the ‘V’ is not acute. Each edge or plane of the ‘V’ of thegasket 7636 is raised by a few degrees only (e.g. 5 to 10 degrees). Thepillows 7611 are mounted one on each of the two planes, and are in thismanner included inwards towards one another slightly in the mostpreferred form. Although there are of course many other ways in whichthis could be achieved without creating a ‘V’ shape.

In the preferred form, as described above, the nasal pillows and thegasket 7636 are formed as a one-piece item. However, the pillows 7611could be removably connected to the gasket 7636, either individually oras a pair. For example, the gasket could include a pair of stub bases towhich the pillows are press-fitted in use, the stub base and the base ofthe stem 7613 being mutually adapted to connect together by way of apress-fit, a keyed connection, or similar. This would potentially allowpillows which are of different shapes or sizes to be fitted to thegasket 7636. This would be advantageous if a user required pillowsmoulded specifically to the shape of their nares, or pillows ofdifferent sizes. This would also allow a range of standard pillows to bemanufactured, the range having different sizes or different shapes, orboth. This would provide a range of off-the-shelf adjustment.

The rear of the gasket 7636 includes a lip cushion 7638, which is arounded elongate surface on the rear of the gasket 7636, the lip cushionresting on the upper lip of a user in use. In the most preferred formthe lip cushion 7638 is hollow and formed from the same supple andflexible material as is used to form the gasket and pillows. The lipcushion 7638 rests against the top lip of a user in use. Detail of thepreferred form of lip cushion 7638 is particularly shown in FIG. 83.

The lip cushion could, in alternative forms, be formed from foam orsimilar.

5.11 Gasket and Manifold Connection

In the most preferred form, as outlined above, the gasket 7636 isstretched over the top of the rear opening or open face of the manifold7608. The gasket 7636 (and pillows 7611 in the most preferred form)could be overmoulded over the top of the manifold 7608, or bump-fittedor push-fitted into place. In the most preferred form shown in FIG. 82a, the lower rear edge 7640 a of the gasket 7636 (which also forms thelower rear part of the lip cushion 7638) slots into a corresponding slot7641 in the rear wall of the manifold 7608. In an alternative form, asshown in FIG. 82b , the gasket 7636 could be connected at the rear ofthe manifold 7608 in the following manner: the inner surface of thegasket 7636 includes a protrusion or bump 7650, which ‘hooks’ over thetop edge 7651 of the rear wall 7652 of the manifold 7608 to hold thegasket 7636 in place. In this first alternative form, the lower rearedge 7640 b of the gasket 7636 is free hanging, unattached orunconstrained, and rests freely against the rear face of the manifold7608 when pushed against the rear wall 7652, e.g. by the pressure of auser's lip.

In the preferred embodiment described above, and as shown in FIG. 82a ,a slot for receiving the lower rear edge 7640 a is described and shown.However, either a top and a bottom slot and tongue could be used, or oneor the other (upper or lower). The tongues and slots would notnecessarily run the entire width of the manifold and gasket, but wouldrun part of the width, or several corresponding tongue/grooves could beused across the width.

As shown in FIG. 83, the lip cushion 7638 is formed as part of thegasket 7636, extending from the top rear edge of the gasket 7636 in use,and looping outwards and downwards to touch or connect against the rearwall of the manifold 7608. The lip cushion 7638 and the manifold 7608 inthe most preferred form as shown do not include a gas path between theinterior of the manifold 7608 and the interior of lip cushion 7638. Thelip cushion is sealed from the flow of gases which passes through theinterface to a user as shown in FIG. 82a . However in alternative forms,as shown in FIG. 82c , there could be a gases path 7660 between the twoso that the lip cushion receives part of said flow of gases in use. Thiscould be advantageous in some forms as it would allow the use of thethin walled lip cushion 7638 which would inflate or partially inflate asgases from the manifold 7608 pass into the interior of the lip cushion7638 and provide an inflation pressure.

5.12 Lexicon

‘Supple’ and ‘flexible’ as they are used in this specification withreference to the nasal pillows 7611 should be taken to mean that, forexample the pillows 7611 or the side support arms 7615, 7616 can besubstantially and repeatedly deformed. For example, by a user pinching,squashing or crushing these in their hand. The pillows and side supportarms return to their original shape with little to no plasticdeformation occurring.

An item having rectangular or square cross-section, with a thickness of1 to 2 mm and a length of 5 cm or more, formed from a ‘supple’ or‘flexible’ material as it should be understood in this specification,will, if held at one end, bend to an extent easily appreciable to thenaked eye, i.e. at least 2 to 3 mm. If it does not bend to anappreciable extent, then it is a rigid or semi-rigid material for thepurposes of this specification, see below.

It should also be understood that ‘flexible’ is intended to mean amaterial that is soft, supple and flexible enough that each of the armscould be rolled into a tube, starting at for example the outer end, withsufficient bending that the end fold completely back on itself so thatthere is little or no central ‘hollow’ portion in the tube formed by therolling. When the tube is unrolled there would be little to no plasticdeformation of the material.

‘Rigid’ as it is used in this specification should be understood to meanthat an item described as rigid can be elastically deformed, but that itwould require application of an external force apart from gravity (i.e.its own weight). To do so a ‘rigid’ item will not collapse or bend underits own weight, in any orientation. It is noted that all items usuallydescribed as rigid have a certain degree of elasticity, but the elasticlimit will normally be reached before the elastic deformation of therigid material is appreciable to a user. Glass, for example, willshatter before the average person is able to appreciate that it haselastically deformed at all. An item having rectangular or squarecross-section, with a thickness of 1 to 2 mm and a length of up to 10cm, formed from a ‘rigid’ or ‘semi-rigid’ material as it should beunderstood in this specification, will not bend to an extent easilyappreciable to the naked eye. For example, the arms of the Fisher &Paykel Opus™ interface or the ResMed Mirage Swift™ II interface arearound 10 to 11 cm long and have a thickness of 1 to 2 mm. The arms ofthese devices are formed from a plastic having a rigidity so that theywill not bend under their own weight if held at one end, and for thepurposes of this specification can be considered to be ‘rigid’ orsemi-rigid’.

‘Substantially vertically downwards’ as it is written in thisspecification should be interpreted as not meaning absolutely vertical.An angle of 10 to 20 degrees or more off-vertical lies within themeaning of ‘substantially vertical’ as it is used in this specification.

It should also be noted that ‘downwards’, ‘outwards’, ‘inner’ and‘outer’, and similar terms as they are used in this specification referto the mask being worn by a user who is standing up. However, in use theinterface is intended to be used by a user who is asleep and will belying on a bed, either on their back, front or side. The conventionreferred to above (a user standing) has been adopted for ease ofreference.

It should also be noted that the term ‘interface’ as it is used in thisspecification refers either to the interface assembly inclusive of thesupply conduit 7604 and the headgear 7603. That is, for the preferredembodiment, the term ‘interface’ could refer to the manifold 7608, thegasket 7636, support arms 7615, 7616 and pillows 7611 in combinationwith the headgear 7603. Alternatively the term ‘interface’ as used inrelation to, for example, the preferred embodiment could refer to themanifold 7608 and the connected gasket 7636 and pillows 7611 and supportarms 7615, 7616 only. That is without the headgear 7603 and the supplyconduit 7604.

6. Nasal Interface with Nasal Plugs

In a general form, a nasal patient interface includes a connector piecethat connects the nasal patient interface to the breathing circuit,transportation passageway or conduit, which is then connected to thesource of pressurised gas.

A nasal plug type nasal interface has nasal members that usually have atype of tapered end that terminates in an aperture (cannula). In use,when a patient inserts each of the nasal plugs into their nasal cavitiesand positive pressure ventilation therapy, oxygen therapy or the like iscommenced, gases pass through a conduit, into a connector, through eachof the nasal members exiting into the patient's nostrils through eachnasal cannula. Thereby administering positive pressure ventilationtherapy, oxygen therapy or the like to the patient.

In general, nasal plugs made from a foam material are known. Forexample, foam nasal plugs are disclosed in U.S. Pat. No. 4,782,832 andWO2003/041780. In use, a foam nasal plug provides a seal between a nasalcavity and the cannula, effectively eliminating gases leakage yet iscomfortable for the patient. The expanding foam provides an outwardforce upon the inner surface of each of the patient's nasal cavities,which also prevents each plug from falling from the nasal cavity.

The nasal plugs of the present invention are adapted to fit a mask andheadgear arrangement. One such example is that mask 8051 shown in FIG.85. The nasal plugs 8050 can be of any of the embodiments describedherein. The mask and headgear arrangement will usually include a mask8051 including nasal plugs for insertion in the patient's nares,headgear 8052, holding the mask 8051 in place, an elbowed connector 8054and conduit 8053 supplying gases to the mask 8051.

FIGS. 86 to 88 show three forms of a nasal plugs 8100. The nasal plug8100 of the type that in use is fitted inside a patient's nasal cavities(nares). The nasal plug 8100 is of a generally cylindrical shape.However, other appropriate shapes, such as ellipsoidal, conical orspherical are envisaged.

The nasal plug 8100 has a body 8101 that is made of a foam typematerial, such as an open cell polyurethane foam. However other foammaterials can be used, for example a silicone foam. In the case of asilicone foam, a skin would be formed automatically, thus the plug wouldbe self-skinning.

The plug 8100 is tubular with a curved tip 8105 resembling a dome. Atubular bore 8102 extending centrally through the plug. When in use, thebore allows gases to flow through the plug 8100 to the patient.

The plug 8100 is comprised of an inner body 8101 and an outer coatinglayer cover or skin 8103 formed about the inner body 8101. The skin 8103may be made from a plastics material such as a thermo plastic elastomer,for example, Kraton or Santoprene, or from a polyurethane or a thermosetplastics, such as silicone.

The skin 8103 can be applied by spraying or dipping after the foam bodyhas been formed. Alternatively, a skin can first be applied to a plugmould, then after some drying time, a foam inner injected, resulting ina coated foam plug 8100.

The skin is preferably a thin coating relative to the size of the nasalplug.

The skin provides a barrier between the foam and the patient's nose. Theskin may provide comfort advantages and will prevent nasal fluid orhumidified air from penetrating the foam, preventing deterioration.Therefore, a coated nasal plug will be more durable.

In FIG. 3, the nasal plug 8100 is shown having a skin 8103 around itsouter surface but not on the bottom surface 8104 of the plug 8100. Anopen bottom surface 8104 allows air to flow in and out of the foam bodyso that its shape can be compressed or expanded to a greater degree.

A second form of a nasal plug is shown in FIG. 87. This nasal plug 8110is tubular with a curved tip resembling a dome. It has an inner body8111 and a central tubular bore 8112 through it. The nasal plug 8110 hasa coated surface, cover or skin 8113. The whole external surface of thefoam nasal plug including its bottom surface 8109 is covered in the skin8113.

The skin has perforations 8114 to allow air to flow into the foam innerto assist in expansion and compression of the nasal plug. Theperforations can be set out equidistantly along the coated surface as isshown in FIG. 88, but can be randomly placed or formed in a non-uniformmanner in the skin.

A third form of a nasal plug is shown in FIG. 88. The nasal plug 8115has an inner body 8116 made of foam. This nasal plug 8115 is tubularwith a curved tip resembling a dome. It has a central tubular bore 8117and a coated surface, cover or skin 8118. The skin has perforations8119. The bottom surface 8120 of the nasal plug 8115 is not coated.Therefore, this embodiment provides the advantage of allowing more airto enter and exit from the bottom of the foam plug. The perforations8119 in the coating may be placed randomly or in the uniform manner asshown in FIG. 88.

FIGS. 89 to 101 show different shaped nasal plugs. These nasal plugs areof a similar construction as those described above. That is, they have afoam inner core or body with a tubular bore for the passage of air.These nasal plugs also have an outer coating, cover or skin preferablymade of a plastics or silicone material. In some forms these nasal plugsmay also have perforations in the skin. The skin covers the bottomsurface of the nasal plugs in some configurations. In others the coatingdoes not cover the bottom surface. The perforations may be placeduniformly or randomly in the skin.

FIG. 89 shows a nasal plug 8120 that has a head or sealing part 8121that is substantially spherical in shape. The diameter of the plug 8120reduces along its length creating a trough 8122 at the centre of theplug. The diameter then increases toward its end or bottom surface 8123.Insertion of this plug into a patient's nares is made easier by reducingthe surface of contact between the plug and the nares.

In FIG. 90 the nasal plug 8125 has a more extreme contour than the nasalplug 8120. The plug 8125 has a spherical head 8126 and trough 8127. Thehead or sealing part 8126 is substantially spherical in shape. The endor bottom of the nasal plug 8125 has a rectangular cross-sectionalflange such that the edges 8128, 8129 of the flange abut the outersurface of a patient's nares in use. This embodiment offers a moreaggressive seal against a patient's nare walls than the nasal plug ofFIG. 89. The radiuses used to design the curves L1 and L2 can vary fromzero to infinity.

FIG. 91 shows a further embodiment of a nasal plug 8130. The nasal plug8130 has a narrow bottom section 8131 and quickly expands along itslength to a larger diameter and dome like tip 8132. The length L3 is asealing length, the length that in use seals in the patient's nares. Theincreased sealing length of this configuration maximises its sealingcapability. An optimisation of this length keeps the plug easily withinthe patient's nares. Also, optimisation of the sealing length may keepallergy or irritation levels marginal or non existent.

FIG. 92 shows yet a further form of a nasal plug 8140 where the plugseals along the nares wall and about the outer circumference of thenares. The nasal plug 8140 has a flange or lip 8141 at its end that inuse will protrude from a patient's nares. The lip 8141 transfers part ofthe pressure applied on the nares wall to the outer circumference ofnares. It is believed this provides less irritation to the patient'snares. In the embodiment of FIG. 92 the tip has a square cross-section8142.

FIG. 93 shows an alternative nasal plug to that plug of FIG. 92. Thenasal plug 8145 has a flange or lip 8146 that is more curved in shape tothat of FIG. 92. The length of the nasal plug 8145 reduces in diameterto its tip 8147 thus giving the nasal plug a conical shape. The conicalshape of the length to the tip allows easy insertion of the nasal pluginto the patient's nares.

FIG. 94 is yet another nasal plug that is of similar configuration tothat of FIG. 9. The nasal plug 150 has a flange or lip 151, but its tip152 is curved in cross-section so the tip 152 is spherical in shape.

FIG. 95 shows a further embodiment of a nasal plug 8200. The nasal plug8200 is conical in shape with a curved tip 8201. It has a tubular borerunning through it in order to supply gases to a patient. The nasal plug8200 has a flange or lip 8202 at its bottom end. The nasal plug 8200 hasan inner body 8203 made of a foam type material, such as an open cellpolyurethane foam, but other foam type material may be used. This regionimmediately surrounds the tubular bore 8205. A coating, cover or skin8204 encases the inner body 8203. The skin is made from a plasticsmaterial or silicone. The skin 8204 forms the flange or lip 8202 of thenasal plug.

The nasal plug 8210 of FIG. 96 is of the same shape as that of FIG. 95.However, the inner foam region or body extends out at the nasal plugsbottom into a lip 8211. The nasal plug 8210 has a cover 8204 thatfollows the contours of the inner foam region 8211.

The embodiments of nasal plugs of FIGS. 95 and 96 can includeperforations in the skin so as to allow air to flow into the foam innerregion to assist in expansion and compression of the nasal plug. Theperforations may be formed uniformly or randomly in the skin.

Yet another form of a nasal plug is shown in FIGS. 97 to 101. In allthese figures the nasal plug 8160 has the same shape. The nasal plug8160 has a tip or head 8166 that has a curved profile that approximatelymatches the shape of a nasal cavity. In use, the tip or head 8166 isfitted in the patient's nares. Additionally, the nasal patient interface8160 has a flange 8161 that seals at the inlet to the nare about theexternal surface of the nare. The sealing capability of this embodimentis such that it helps to maximise the seal and the patient's comfort.

The nasal plug 8160 has a tubular bore 8167 through it to allow forgases to flow through the plug.

This embodiment of the nasal plug 8160 has a coating, cover or skin8163, preferably of plastic or silicone, but other materials may beused. The skin substantially covers the external surface of the nasalplug 8160.

In FIG. 97 the nasal plug has a foam body 8162 and an outer skin 8163.The skin 8163 extends completely about the foam inner 8162.

In FIG. 98 the skin 8163 on the nasal plug 8160 does not extend over thebottom surface 8164 of the nasal plugs.

In FIG. 99 the skin 8163 on the nasal plug 8160 does not extend over theinner surface of the tubular bore 8165.

In FIG. 100 the skin 8163 on the nasal plug 8160 does not extend overthe surface of the inner bore 8165, nor on the bottom surface 8164 ofthe nasal plug 8160.

FIGS. 106 and 107 show additions to the nasal plugs of FIGS. 97 to 101.In the embodiments of FIGS. 106 and 107 the nasal plugs 8190, 8195 eachhave an external circumferential flap 8191, 8196. The flap may be one oftwo configurations, a tip-jointed flap 8191 of FIG. 106 or aflange-jointed flap 8196 of FIG. 107.

FIG. 106 shows a nasal plug 8190 of the same configuration as FIG. 98,but including a tip jointed flap 8191. The flap 8191 extends from thetip 8192 of the nasal plug 8190 out toward the flange 8193.

FIG. 107 shows a nasal plug 8195 of the same configuration as FIG. 98,but including a flange-jointed flap 8196. The flap 8196 extends from theflange 8197 up towards the tip 8198. This configuration provides aparticularly good seal when the patient is exhaling in use.

The flaps 8191, 8196 are constructed from a flexible plastics material,such as silicone, although other suitable materials may be used. Theflaps are hinged to the tip 8192 or flange 8197 and so can be moved awayor toward the corresponding flange 8193 or tip 8198.

Each of the nasal plugs can be covered to give it additional durability.The nasal plugs have an inner body 8194, 8199. The inner body isconstructed from a foam type material, such as an open cell polyurethanefoam or silicone foam. The plugs each have a cover, coating or skin8200, 8201 made from a plastics or silicone material. In the case of asilicone foam, a skin would be formed automatically, thus the plug wouldbe self-skinning.

The skin 8200, 8201 about the inner body can include perforations toallow for air to flow into and out of the inner body. The perforationscan be formed in a uniform or non-uniform manner in the skin.

The flap, of either embodiment of FIG. 106 or 107, is formed integrallywith the skin of the nasal plug 8190, 8195. For forming or moulding ofthe nasal plug, a mould includes one region for the flaps and anotherfor the body of the nasal plug. A plastics or silicone for the skin isinjected into the mould, lining the mould and creating the flaps. Then afoaming type material, such as open cell polyurethane foam, is injectedinto the mould. The result is a foam nasal plug covered in a skin with acircumferential flap. To allow for injection moulding of the nasal plugsin this embodiment the bottom surfaces of each of the embodimentsdescribed must be open.

Once a nasal plug is in place in the patient's nares, the flap will restagainst the body of the plug in a closed position, providing a secondlayer or wall that increases both the comfort of the patient and seal ofthe plug in the patient's nares. Also, the flap allows for adaptation ofthe nasal plug to a wider range of nare diameter.

FIGS. 86 to 101, 106 and 107 are single nasal plugs. In use, it ispreferred that two are used. However one may be all that is required fora particular application. In the preferred form two nasal plugs areattached to a body or manifold of a patient interface, such as thatmanifold 8055 as shown in FIG. 85.

In a further form a nasal plug 8170 is shown in FIG. 102. The nasal plughas a body 8183 made from a foam type material, such as an open cellpolyurethane foam, or a silicone foam. In the case of a silicone foam, askin would be formed automatically, s thus the plug would beself-skinning.

The nasal plug 8170 has a gases inlet 8175 capable of receiving gasesfrom a conduit or tubing. The nasal plug has two nasal members 8171,8172 separated by a cavity 8173. The inlet 8175 is a tubular bore 8176that is bifurcated. Each of the branches 8177, 8178 of the bifurcatedbore 8176 extend one each into one of the nasal members 8171, 8172. Eachbranch 8177, 8178 of the tubular bore terminates in a gases outlet 8179,8180.

Below each of the nasal members 8171, 8172 is a flange or lip 8174.Therefore, the nasal interface 8170 has an overall y-shapedconfiguration. This configuration is such that it's curved profileapproximately matches the bottom of the nose and nasal cavities of ahuman.

In use, the nasal members 8171, 8172 extend into both of a patient'snares and the cavity 8173 receives the patient's nasal septum. The lip8174 rests against the outer surface of the nares to seal on the narisof the nose.

As the nasal plug 8170 is predominantly made from a foam type materialthe foam can to be deformed during insertion of the plugs in the nasalpassages and the foam will expand and mould to the shape of the nasalpassages.

The nasal plug 8170 can be provided with a coating, cover or skin 8181extending completely about the exterior surface of the interface. Thecoating 8181 is made from a material such as a thermo plastic elastomer,for example, Kraton or Santoprene, or from a polyurethane or a thermosetplastics, such as silicone, making the nasal plug more durable. FIGS.104 and 105 show two different coatings. In FIG. 104 the coating 8181extends completely about the external surfaces. In FIG. 105 the coatingdoes not extend along the bottom surface (or inlet 8175 surface) 8182.The absence of coating along the bottom surface will serve to allow moreair movement into and out of the foam body, allowing for betterdeformation and expansion.

The coating can have perforations to allow for air to flow into and outof the foam body.

The nasal plugs of FIGS. 102 to 105 are formed by injection moulding.The foam is injected into a mould to make the body of the nasalinterface. In the embodiments with an outer coating, the plastics orsilicone for the coating is injected first into the mould, then thefoam, resulting in a coating foam nasal plug.

For any of the nasal plugs as described herein (FIGS. 85 to 107), touse, a patient need only apply pressure to the sides of a nasal plug,depressing the foam and deforming the shape of each of the nasal plugsso that each is easily insertable into each nasal cavity. Once each plugis within each cavity the foam will expand to its original form wherethe external surface of the foam abuts the internal surface of thepatient's nasal cavity, filling the area within each nostril. Thesenasal plugs substantially seal in the patient's nasal cavity, but insome forms may not form a complete seal, or seal at all.

In other forms the nasal plugs of the present invention as describedherein, may not extend into the nares of the patient, but rest againstthe patient external surfaces and abut against the patient nares.

What is claimed is:
 1. A patient interface for supplying a flow ofrespiratory gases to a user comprising: a gasket portion arranged toreceive the flow of respiratory gases; a pair of pillow portionsconnected to and extending from the gasket portion, the pillow portionsarranged to receive the flow of respiratory gases from the gasketportion and provide the flow of respiratory gases to the user, each ofthe pillow portions being defined between a lower end at which each ofthe pillow portions connects to the gasket portion and an upper endcomprising an upper opening of each of the pillows portions; and atleast one rib disposed in one of the pillow portions, the at least onerib configured to provide rigidity to the pillow portion and to limitthe collapse of the pillow portion, in use, the at least one rib havinga first end and a second end, and an upper surface and a lower surfaceextending between the first end and the second end, wherein the at leastone rib extends from the first end at a first location to the second endat a second location, the first and second locations being located on aninner side of the pillow portion, the first location being locateddiametrically across from the second location, wherein the at least onerib lies within the flow of respiratory gases delivered to the user witheach of the upper surface and the lower surface located between theupper end and the lower end of the pillow portion, and the at least onerib is curved between the first location and the second location.
 2. Thepatient interface of claim 1, wherein the height of the at least one ribvaries along its length from the first end to the second end.
 3. Thepatient interface of claim 2, wherein the height of the at least one ribincreases towards the inner surface of the pillow portion.
 4. Thepatient interface of claim 1, wherein the at least one rib has across-sectional thickness that varies along its length.
 5. The patientinterface of claim 4, wherein the cross-sectional thickness of the atleast one rib increases towards the inner surface of the pillow portion.6. The patient interface of claim 1, wherein the at least one rib isrounded and the first and second ends blend with the inner surface ofthe pillow portion.
 7. The patient interface of claim 1, wherein the atleast one rib extends downwardly from a position below the upper openingof the pillow portion.
 8. The patient interface of claim 1, wherein theupper surface of the at least one rib is curved between the first endand the second end.
 9. The patient interface of claim 1, wherein thelower surface of the at least one rib is curved between the first endand the second end.
 10. The patient interface of claim 9, wherein thelower surface of the at least one rib is curved upwardly.
 11. Thepatient interface of claim 1, wherein the at least one rib extendsacross an entire diameter of the pillow portion.
 12. The patientinterface of claim 1, wherein the at least one rib is offset from anotional diametrically aligned centre line of the pillow portion. 13.The patient interface of claim 1, wherein the at least one rib has across-sectional thickness that is greater than a cross-sectionalthickness of the pillow portion.
 14. The patient interface of claim 1,wherein the at least one rib has a larger cross-sectional thickness at abase than at a top edge.
 15. The patient interface of claim 1, wherein across-sectional thickness of the pillow portion tapers from the lowerend towards the upper end.
 16. The patient interface of claim 15,wherein the cross-sectional thickness of the pillow portion is thickerat the lower end than at the upper end.
 17. The patient interface ofclaim 4, wherein the cross-sectional thickness of the at least one ribis wider at the first and second ends than at the center of the at leastone rib.
 18. The patient interface of claim 1, wherein a cross-sectionalthickness of the at least one rib differs at different heights of the atleast one rib.